John in NM
Is called plastic resin glue - it's fantastic stuff.
Except when mixed too thin with water, that makes it weak, or as you found, when used below it's ambient temperature range, then it doesn't adhere well. I had the same problem as you describe once when using it below the recommended 70 F - but not that far below, in the low 60's as I recall. Powdery glue joints, but just at the edges of the veneer where the too low ambient temp had the greatest effect.
I think it's not intended as a consumer product, so the manufacturer did not put a "buffer factor" in the instructions. When they say do not use below 70 F, they really mean it! Same with the strict recommendation to weigh glue powder vs. water rather than attempt to mix by volume. It works much better when measured by weight.
All probably water under the bridge now, just wanted to confirm your speculation with my own similar experiences.