I encountered this a couple of months ago when I first got back into this.
At that time I cannot recall what the batch was from but since then I have been using the ally pan and not really experienced it again.
This time though it was a 40/50 mix with oil and no water added, I chose to start off a spag bog with it and it spat so much I had to take cover and throw a lid on a bit quick.
It maybe just me, just an observation.

---------------------------------------------------------------------
Come to think of it I'll do a side by side test tomorrow, I do love an experiment!