An obvious question, but I still think it’s worth asking.
Did you try swapping the batteries between the readers?
If so does the problem follow?
Maybe lower voltage may be causing the reading problem 
or of course, did you just change the batteries?
UPDATE
I wrote this before seeing your message above.
So yeah, sounds like a chip issue
after the update to set the reader in a higher frequency the batteries went from 3 bars to 0 in a week. So i replaced them with new and better batteries.
yes seems like it 
I hope my cat is ok tho… he has lost a lot of weight fast and i thought it was because he couldn’t eat when he wanted to.
When a chip is there for so long doesn’t there grow scar tissue around it and keeps it on its place?
I cant make a new reply anymore cause its my first day but yes to your question @Pilgrimsmaster
@amal nope, 16 more hours wait
So one cat/chip can eat/read from both feeders, and the other cat/chip cannot?
Try now.
Strange… , I changed you from a 0-new user to a 1-basic user, you SHOULD be able to post and reply
I checked earlier today and i still had 4 hours left and couldn’t reply. Thanks for trying tho 
As for the chip, im gonna have to check with the vet and until then he will have to wear the collar 
I’ve seen really cool stuff on this forum and this is probably the least interesting topic for you guys haha… But i still would like to give an update.
So i went to the vet and he couldn’t scan the chip either. Told me it was broken and gave Devil a new chip.
I got home and tried to add Devil with the new chip to his feeder, but still nothing.
Tried my other cats feeder, also nothing.
Called the vet and they said sometimes the chip falls out of the wound. Ok sure i went by and the scanner still scanned it.
Went back home. Tried adding Devil to the feeders again but nothing happened.
So now im back at square one, no idea where the problem lies. And emailing Surepetcare again.
Thanks for the update.
It is possible that the vets scanner is more easily able to pick up the new chip than the bowls are. Normally we tell humans to wait at least two weeks for the swelling to go down before trying to read the chip. I don’t know if that is good advice for a pet too.
I didn’t think about that as a possibility. And this could be really helpful advice. Thanks!
I already emailed surepetcare and they suggest a reset of the bowl and if that doesnt help they can add his chip id. Even if they do that its gonna have to scan his chip each time he wants to eat so im not sure if that will help.
Im just waiting for a reply about the serialnumber update of the bowl. Cause i dont know if i reset if it will erase that update too. 
But i will definitely keep this in mind and try again in a week and in 2 weeks.
Personally, I find it quite interesting.
I look forward to the updates, and I hope it all goes well
Hahah right?!
Obviously they don’t have any idea how to solve this problem.
Im glad it’s still interesting for people here.
I saw all these videos of people opening doors and cars, paying and turn on the music and then here i am with my cat 
Beware,
That forum may well turn you into a cyborg cat longing for a hacked up fridge.
Meow.
Im ok with that. As long as that fridge is filled with treats.
Ok a little update…
Today i reset the feeder, took off devils collar with tag and let him eat treats from the bowl while it was in “Add Mode”.
After about a minute it added a new chip with a different number than my cats chips.
Nothing else but my cat, my phone and i were close.
But ok, i thought that still must be his new chip anyway.
So i put new treats in the bowl so he would eat again to test if it would open and it didn’t. Took more than 1,5 minute before he walked away.
I put the feeder in “Add Mode” again and he comes and eat the treats AND HIS OLD CHIP GETS ADDED! (Yup the one that was declared dead)
Then i try to get him to eat again in normal mode and it opens almost right away.
I guess i need to wait and see if it will stay this way.
Idk what that other number was tho. It looked more like a tag number than a pet chip number.
Working like it should
Also, the “new tag” that was added is there a chance that there is a tag anywhere near ? Sounds like the reader is just adding noise tbh.
No like i said it was just me, my phone and Devil without the collar and tag. So his 2 chips should be the only things it would detect.
The scanner range is not far enough outside the feeder to detect anything else.
I borrowed a chip scanner to check Devil’s chips myself and still I can only see the new one. And also still the Surefeed will only read the old chip but after more than 1,5 min.
I got an email back from the Surepetcare customer service saying that sometimes when animals have more than 1 chip 
they can disturb (not sure if this is the right English word for it) each other.
That doesn’t sound logical to me. If the older chip is harder to read (weaker?) should the newer chip still be read? Maybe the old one would be in the way of reading the new one well each time but at least it should have picked it up instead of the old one.
Is there some physical issue a person(or animal) can have that would be bad for a chip? Like some kind of disease.
Sure pet care tells me that best is to keep using the tag and that’s it.
I just want to figure out what the hell is going on lol
If they’re close that can happen. We know that from human chips.
It’s called collision, and low frequency chips rarely support any kind of anti-collision features. Basically both chips try to *talk" at the same time and the signal gets mixed and basically turns to noise.