I keep having issues with the Weber!

I continue to develop vacuum leaks. The first time , it was probably my fault for boogering the gasket. I re ordered a gasket set and did everything strictly by the book.

That seemed to fix the issue, but about 6 months later I face the issue of mounting bolts backing out of the adapter plates!
I loctited them and tightened them accordingly.

I have taken everything apart again and reordered the gasket set. I've cleaned everything including the bolts and all mounting surfaces and just wait for new gasket to come in.

Does anyone have any suggestions for me as I attempt to do this for the 3rd time?