First rep of shoulder press

Hello

I recently started strength training again and am doing regular singles and triples for barbell strict presses.
However, i encountered a problem that I do not seem to have with the other main lifts.
For some reason, I have a lot of trouble lifting up my first rep of the press.
Lets say I am working up to 4@9 at 100kg. I can barely lift the initjal rep up, and I often almost fail the rep. BUT, if I do lift it up, for whatever reason, i could easily lift up the 2nd, 3rd and 4th rep, to a point where its not even an rpe 9 anymore, since I would be able to do 2 or 3 more reps easily. But if I go heavier, for the set to be a true rpe 9, i would almost certainly fail the first rep.
I am super confused by this, since it literally only happens with this exercise.

I dont know if its a technique issue or just mental. I dont seem to change my technique between the first amd the remaining reps. It just feels like I have less strength at the beginning.
I also dont bounce the barbell after the 1st rep or use any kind of momentum.

Is this common? What do you guys think i could do to fix this?

Thanks!
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It could be a technique issue (for example, if you’re starting subsequent reps in a different position, if you’re not fully resetting between reps and getting a bit of a stretch reflex / bounce on subsequent reps, etc.), or it could be something that just needs more specific practice with heavy singles over time.

This would be actually be a good topic for one of our coaches to discuss with you via our coaching consult service, where they could potentially give more specific advice based on how things look.