Front brake slide pins

This is regarding the front brakes on my 2015 Trailhawk.

About once a year (when I switch between summer and winter tires -either way) I pull my calipers off and lubricate the slide pins with the Permatex purple "extreme" brake lube.
For the last couple of seasons, when I unbolt the calipers, the slide pins (top and bottom on both sides) won't slide by hand. They require a tool to grab them and slowly work them out of the carrier.

So, here's the thing... Once I get them out and moving they slide in and out super easily. Just the pressure built up by the slide pin retracting is enough to force them back out (like a hydraulically locked piston), but until they are freed up they are as stiff as frozen sh*t. I can't imagine they are allowing the caliper to move back and forth properly. When I get them out, they still have purple grease on them. It doesn't appear contaminated and the slide pins don't show any sign of unusual wear. Plus, it's all four front slide pins acting the same.

I read about bent slide pins online, but I don't think that is my issue because after they are moving - they move super easily. I pull them out and regrease them. Even before I regrease them, once they are freed up they move like butter. As they go back in they seem like happy campers, but come to the next inspection- they won't budge without some force from channel lock pliers.

I do the same with the rears and they have always been smooth as silk upon initial inspection.

I work on a lot of mechanical things, but I'm really just a shade-tree mechanic and don't have a ton of experience to draw on. What do you people think is going on with my front slide pins? Should I just get new ones and see if there is an improvement? Is this normal (it's not in my experience with other vehicles)? Looking for your opinions. Thanks.