That reminds me a bit of a very awkward GM decision I witnessed about a magic/summoning rule in DSA/RoA, where there is a spell that allows you to create an area or material (like, freezing parts of a lake to walk over it).
And there is a spell that lets you summon elementals given enough material of their element.
But the GM would not allow to first freeze some water and then create an ice elemental from it because that is not explicitly written in the rules.
We did not play with that GM for very long...
I had a good GM who did listen and was the complete opposite of that.
I recall casting Animal Growth on Bob and having him jump from the cave's roof (he was wearing Slippers of Spiderclimb) onto the BBEG. 1,600lb brown bear enlarged one size up = something like x32 weight gain (it is actually in the 3.5 rules). Every 200lb is 1d6 damage, every 10ft drop after the first 10ft is 1d6 damage. Ended up with 260d6 squashing damage or something absurd like that. His BBEG ended up a literal smear on the ground.
He tried to turn the tables on me later by having a Roc (yes, the massive bird) drop on me after I killed it in mid-air (wizard vs Roc aerial combat). I pointed out that as I had the Fly spell on, I would be a point of resistance and the dead Roc would basicaly pivot around me and fall past me, so no damage. To his credit, he accepted that