This ^
I’m pretty sure soft plastics are more susceptible to silicone lube damage than silicone toys are. I personally would only use water-based lube for soft plastics. 
The head master is a slightly different material to Fleshlights, but I still think it’ll degrade it over time.
When I did my silicone test on silicone toys it was over an extended period (finishing with a 24hour test).
In fact, I’ll have a root around and see if I can dig out a similar stroker to douse in some silicone and see what happens. 