Using a mySQL database and it seems like playtime events are not being triggered.

Login events are being triggered every time logging in, regardless of if repeat is on or not. Settings are as follows:
events:
enabled: true
interval: 600

I waited twenty minutes and still was not rewarded, tried making an event to give diamonds 5 minutes from my current playtime but did not receive.

Thoughts on how to troubleshoot this?

Login events, by default, occur upon every login. I suppose I could have that intertwine with the repeat function, but alas that isn't the actual issue here.

You need a lower interval. The interval checks every x minutes, where the x is the number you provide. that means that within your check it would only fire events every 600 minutes (a fairly unstable check at that, hitting around 10 hours). Try using the default 10.

I'll give it a shot and let you know if that fixes it.

Yep, I assumed it was seconds to coincide with the other values on the config. Thanks for the quick response!

The reasoning I didn't allow for seconds is the implementation currently isn't the best. If people decided to set 1-second interval checks they would crash their servers.

Glad to see you got it working :)