2k Acrylic Paint Kit Direct High Gloss.
ISOCYANATE FREE Hardener
This paint has been introduced for customers who require the high gloss finish - durability and colour matching of conventional 2k materials without the health concerns associated to Isocyanated hardeners. None isocyanate hardener converts a two pack activated paint into an air dry paint. The drying and cure times can take much longer depending on the weather conditions. It is recommended that you use the same spraying technique as you would with synthetic air dry oil based paints. Do not apply heavily; allow to flash off between coats. Like synthetic paint if you attempt to speed up the drying process you will slow down the overall time it takes to fully cure.
Please note this paint will not dry without this special isocyanate free hardener or a suitable 2k acrylic paint hardener been added. Recommended Application: Spray, Mixing Ratio: 2 parts paint 1 part hardener and 15% 2k thinner.

I can't say for the specific iso-free clear that you're talking about but I did use one some years ago that was absolute garbage. Apart from being yellow it was difficult to use and could not be re-worked for weeks after application.

Given the health risks with isocyanate I would think that the paint companies would jump at a product that was iso-free and worked. That they haven't says to me that it probably isn't a good choice.

Yeah, I've been waiting for years and years for an Iso free clear that actually worked. It would be a "word from God" moment for consumers, hobbyists, paint shops, etc., and I've not seen it yet.