I've been issued a G22 at 3 different facilities. Two had the grip plug. One allowed me to switch out the standard plug for the extended.
The extended one really helped my reloads, and i use it in my personal 19, my personal 22 has Clints magwell.
I never saw an issue caused by the grip plug.
At the site that ddidn't use or allow the plug, I did see problems. Reloads aside, we would run o courses or other training that got us in the dirt. The open backstrap would scoope up enough crude to cause the trigger to either lock up, or become very difficult to manipulate....worse then the usual shitty pull produced by the "+" connector.