I've done an installation of 100m2 bamboo using bostik. The floor started lifting in places and we realised moisture seeping in through the sliding doors and the concrete mixture wasn't done properly so concrete was also lifting. In some places the bostik didn't stick. I am now redoing the whole job with a different glue (Sika). I'm in Cape Town SA and the bostik I received came from Australia. The pales where dry at the top (5-10cm) and I don't want to use this again.

My main issue is how do I get rid of the bostik that is on the subfloor?

Scrape it off.

Razor scraper or a product like Soy-Gel.