In post #29 Seems like you kind of already showed it is related to the relays and switching.
Now take a step back way back.
We need you to fully disclose everything you are doing.
You started off telling us some things in your original post.
But you have now disclosed that you have more components than what you originally stated.
Details really matter. Had you originally told us about the relays we would have gone down different paths to try to find the issue as using relays has many known issues.
Please now post a full details of what this project/code is doing along with a full schematic of everything you have connected and show a few pictures of your project so we can see how things are wired up.
---- bill