Problem with primer on chassis

[tkpm]

Dulux have been making this for few years.
If it had been the cold, the primer will have small crystal in it, i would say it either was a contaminant or it was not stir for long enough as it oil based, and you can only use oil base products as a top coat.

As others have said, use a chassis paint designed for this job or power coating, hammerite is ok, but doles quite quickly.
Terry