Most shaders laggy upon game start, but switching shader then switching back clears it up

[SlowSL]

Rpi3b+ w/ official 4.8
Quality pwr supply
keyboard & ipac4 connected

Haven't really messed with shaders until recently. I spent a good amount of time weeding out the ones I didn't like or didn't work, and left with a handful which work well.

Here is the problem... Whenever I set one as the default (core default), when the game first loads, it's choppy/laggy. I have hotkeys set for next/previous shaders, and If I switch to the next shader, it's fine, move back to the shader that I was just on, it's now fine, game runs smoothly as it should. Exit the game, then open the game (any game), same thing, laggy. Only switching shader and switching back fixes it. So far, most of the ones I've made the default are behaving this way & although I ran out of time last night, I did find one which works as it should, but not my favorite. It would be nice to figure out why it's doing this.