Indesign not exporting tags to pdf

Hi all

Need help with Indesign documents exported as accessible pdf files. I've been producing accessible files for a couple of years now without too many problems (always sorted). But recently after lastest updates to Indesign and Acrobat I've found that when opening the pdf file and checking accesibility tags – the document displays No Tags available? The indesign doc I've set style sheets – added H1/H2 etc and P style for output to pdf (originally I used to leave these as default for Indesign to manage) , but nothing arrives in the pdf – I'm having to manually set all styles and tags within acrobat. Frustrating to say the least. 

Please don't suggest I check the Create tagged pdf in the output to pdf as I have a preset for Accessibles.

Indesign 19.5

Acrobat Pro V2024.002.20964

Imac Ventura 13.5.2

Any suggestions welcome – life has become tiresome with accessibility lately!