Peculiar automatic gate behavior

[Gatefreak]

Hello.
I hope you folk could help me with this weird problem.

A Bernal kings gate sliding gate installed 15 years ago is exhibiting strange behavior.

The gate gets close to closing, but a meter before reaching the end it already slows down like it should when it's much closer.
After a little bit of slow movement, it reverses direction and opens fully again.
Video here

This is somehow connected to temperature as it doesn't really happen in the cold, but the gate goes crazy in the summer or under sunlight.

The gate can be closed by stopping the opening after reversal and restarting closing again and again until it's in the end bucket. It also closes when it is manually helped by pushing or pulling in the closing direction.

Not very gate savvy, how would one go diagnosing this?

[Anthonyhem]

Sveiki visi,

Norejau pasidalinti asmenine patirtimi. Praejusi semestra susiduriau su problema – pritruko lesu studiju mokesciui. Nebuvau tinkamas stipendijai gauti, o darbas ne visada uztikrino pakankamas pajamas.

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Zinoma, visada verta pasidometi placiau, bet man tai padejo ir leido isvengti velavimu su apmokejimais. Gal kam nors irgi pravers.