Font styling changes on its own!

Anyone having an issue where you style text blocks out they way you want with color, H or P tag, alignment, etc and its good until you come back later and it changed? This has now happened on two sites and clients are noticing. Two examples:

1. I have 3 text blocks with a number 1, 2, and 3 in each. They are centered in the block. When I come back after time has passed, they are now left aligned and not displaying over image block that I had aligned.
2. I am using h2 style on 6 text blocks. Come back later and they have changed to p3 styling. 

I have tried deleting and re creating new blocks and removing all formatting but no luck after I hit save! This is a big issue! Any updates or comments from anyone having the same issue?