As long as the Imam is Muslim, you must attend the congregation and leave immediately afterwards without participating with them in any of their innovations.

I stopped going to the mosque as I noticed when I attend regularly I feel a deviation in my heart and I feel lost in my Deen. The mosque is one where mawlid, urs, etc. is celebrated. It happens when I’m out of town for 2-3 days. Then my heart gets settled again and I know again what is good and what is not. Please advise me. I read your article on tricks of Shaitan but I still feel something in my heart.