Posts Are Being Cut Off After Publishing

I’ve been having this occasional recurring problem that has become very annoying and inconvenient. Each time I make a post on my site, portions of the post will disappear when I publish it. It’s happening with any post length, 200 words or 800 words. The latter part of it always cuts off when I publish. I haven’t changed anything or added in any plugins so I don’t think it’s anything interfering.

I contacted my hosting company (Bluehost) and they seem to think it’s an issue with the way the theme is coded and suggested that I check with the developer for “compatibility issues.” Can anyone help me with this??

Now…I’ve switched to the WP default theme. I’ve deactivated ALL plugins. The posts are still disappearing. When I post content on other domains with basic theme, this isn’t happening. I haven’t a clue as to what’s causing this.