Record bugs somewhere
“Hey, the button on the second page doesn’t work.”
“Oh, by the way, when I put numbers into this field and press submit, nothing happens.”
You get busy, and a few days later - what was the bug again? If it was mentioned in a meeting, I know I’ll forget the details unless I take notes. Sure, you can review Slack messages and emails, but the bug reports are interleaved with lots of other stuff.
Centralized bug logging solves this and a lot more. If you don’t like JIRA, use Bugzilla (just kidding). Use something. Have everyone use it.
It’s like version control: something is better than nothing.