why cibc atm almost always reject $50 new bills? have to go turu 4 atm to deposit them. thx

This maybe related. I am with Simplii and use CIBC atm. A couple of their machines did not recognize and rejected cheques (including government cheque). I tried a few time with different cheques over a few months, etc. Same problem (consistent with just those couple of machines), but other machine worked.
I eventually told them about the problem and which machine was affected and it got fix the next month - when I was able to deposit my cheques without issue.
I suggest after you confirm which machines are bad, let them know the details and hopefully they'll fix it.

Most of the time if their not like flat pristine condition doesn’t matter what denomination spits them out same goes for cheques. These new machines suck, they’re saving billions on the envelopes too. I’ll add two times I’ve had these new atms take my cash without updating my balance as if I put no money in there, then had the fun time chasing customer service to credit me back my own money with a “investigation”.