MPDF div not working inside table
Looking for solutions to the same problem I just realized that according to the documentation, it's not a bug, it's a feature limitation:
Block-level tags (DIV, P etc) are ignored inside tables, including any CSS styles - inline CSS or stylesheet classes, id etc. To set text characteristics within a table/cell, either define the CSS for the table/cell, or use in-line tags e.g.
<SPAN style=”…“>
Seems like there's currently no way around it. In my case I had to use s to indent (fake-center) a <h4> headline.