Hi @Boshomi, thanks for taking the time to report this!

Is this problem reproducible / does that still happen if you try again?
What exactly does "update" mean in this context? A simple edit?

I hat to split the page into 3 parts, then it uplade worked.

Could you elaborate what that means, or provide a link(s) showing what this mean?

@Aklapper
I spited the list [[Wikipedia:WikiProjekt_Weblinkwartung/Botliste]]
into
[[Wikipedia:WikiProjekt_Weblinkwartung/Botliste]]
[[Wikipedia:WikiProjekt_Weblinkwartung/Botliste2]]
[[Wikipedia:WikiProjekt_Weblinkwartung/Botliste3]]
(Timestamp of creating the 2 and 3 page)

If you merge the tables into one table, you can reproduce the error

I think the error followed after replace of 28000 "¦" chars by {{pipe}}-template

(by the way: It could be a good idea to detect immutable templates and modules and replace them with constants.)

This sounds a lot like T59499: 503 Error when saving a long page with lots of templates on ml.wp.