Hello,
Not sure I should make a new post or use an existing one, but I'm facing the same problem, with easyblog 5.0.31. It's not very recent, but I can remember it didn't happen on some of the first versions of EB5.
It's something you can even reproduce on the demo website. Here are the steps to reproduce :
1) Make a new post, using a blank template
2) Add a HTML block below the text block where there is "Enter your text here"
3) The block is properly added, but doesn't seems to work as intended. On my first picture, the block appears on the block list, but there is nothing else.
4) Select the text block where there is "Enter your text here". The block list on the right is now updated and shows the complete tree. On my second pic, you can see the block list on the right showing a text block, and a html block.
5) Select the html block on the block list. The field to enter your code appears, and the block is properly selected (3rd pic)
6) Type anything on the field. For my example, I typed "<p>This is a text that should appears on the HTML block</p>" (4th pic)
7) Select the text block on the block list again, then go back to the HTML block. The text previously typed disappeared. Works also if you select another block on the composer, or if you click on "Done editing". Basically, it happens if you unselect the block. The code I typed never appeared on the block that is on the composer.
You can still interact with the block, moving it, dropping it, etc... But you can't type anything on it, since it's just deleted when you unselect the block. After that also, there is some weird behavior of the composer when I try to re-add the block, like, It's not added the first time, or It's not displayed immediatly on the block list, and you must click on a block to refresh the list. Am I doing something wrong, or is there a real problem?