@TBauer seems to be using this experimental branch, so I guess this is fine. It’s still not supported, but I’d like to know what’s causing this error anyway.
@TBauer could you please send me the content of the post_text column in the phpbb_posts table for post with ID 14742 in a PM or post it here?
I’m guessing you recently upgraded to phpBB 3.2 and it hasn’t finished converting the old BBCode format to the new one. That’s why it might fail after 2800 posts. If that’s the case, you might want to run the phpBB 3.2+ Text Reparser in a CLI. The import script currently doesn’t support mixing old and new storage formats for BBCodes and the BBCode to Markdown conversion should work a lot better with the new format. 