Form with a Tab Control is stuck in loop

[Vicar]

I have a main form and a two-tab subforms connected to it. When i had one added, everything was fine, after inserting second one, when i run main form it starts looping-requerying the main form and also it’s subforms.

I have included a clean version, maybe someone can tell me what’s the problem. I do suspect the relationship to the customer table,… new to access. Let me know if someone can figure it out. Just open Main form.

Thanks

V.