Anyone else have gapping issues with Karndean glue down LVT over in floor heat?

Hi everyone. I’m looking into some issues I’ve run into with Karndean glue down LVT flooring installed over in-floor heat. I’ve noticed some gaps appear and grow over time, getting up to 5mm between the ends of some boards. When I checked the installation guidelines I noticed that Karndean has significantly changed their heating ramp up recommendations compared to what was available a few years ago, going from a few degrees per hour to only a couple degrees per day.

Just trying to get a sense of whether this is a common issue or something unique in my case. I’d really appreciate hearing from anyone who’s dealt with similar situations.

Thanks in advance!

 

Which karndean is it ? What adhesive was used ?

 

Few degrees per hour? Not heard of that one personally.

Is that how you introduced the ufh?