Yep, memory cards definitely can cause problems. It would be of interest to know the brand of your and the OP's memory card.The LCD on my E-M5 Mark II stopped working last week. I changed the battery and the lens, but it didn't work anyways. Finally, I reinserted the memory card and it started working again and so far everything's ok. So I believe that the memory card does cause a problem.In any case, the memory card wouldn't cause the LCD to stop working, would it?
I just demonstrated that Lexar 64GB 2000x and 1000x memory cards get corrupted in my E-M5.2 and E-M1.2 when shooting video for up to close to 30 minutes. Switching to Olympus recommended SanDisk 64GB 280 MB/s memory cards solved the problem. In fact due to efforts of forum members Lexar has acknowledged the incompatibility of the Lexar 128GB memory card with the E-M1.2 and issued REV B of that card. I have gotten an RMA number from Lexar and sent in my cards for replacement with the revised cards. Lexar said it typically takes them 2 or 3 weeks to send out the replacements.
i have no idea whether the problems you encountered are related to mine. So good luck with debugging your camera.