Fingers locking up is essentially the exact same mental issue as Lazy Cursors.
Similar to lazy cursor, if you see mainly a pattern, like a stream going into a single or a stream going into a slider. Your hands are forgoing the last bits of that stream in anticipation for that single at the very end, thus the lock up. Similarly, if you force the stream, there's a chance your hand will freeze when you try to hit that single or slider at the end, usually causing a miss.
Other cases include back-to-back appearances for triples, which can muddle up your muscles briefly, almost like the finger version of
Semantic Satiation.
Reading ahead is the biggest offender for not clicking notes when there are nothing but singles and sliders. Reading ahead means that you forcefully apply a little buffer in your mind about when to press a note. The task becomes increasingly difficult as more notes appear on the screen. As you may have experienced firsthand, when a series of singles appear on the screen before you even click, you're setting up a buffer if you're not quite experienced with a map.
As for a solution to this....well.....I'm not a therapist, the issue is definitely mental (unless it's like 280 bpm single taps, then that's a physical issue).
I do have advice for the issue of Reading ahead though. When you read a number of singles that appear on the screen, do not think "I have to click these notes at these times", instead think "When I click these notes in succession, it should sound like this". If you don't really know what it sounds like, then editor and auto are your friends for that