[1.1.6] Gap on transport belt after Inserter picks up Items

[fabi123]

I wondered why my seemingly full belt only outputs 7. After running a 'debugger' with a 'breakpoint' I saw that there was, indeed, a gap on the belt, and after building a test setup, I could reproduce the issue frequently.

A stack inserter picking up from a left turned belt causes a transport belt gap 1 tile away. The gap appears out of nowhere.

Attached is a file halted where the gap exists. 112 ticks after the save another gap will appear on the same belt.

[fabi123]

I tried it again without mods, still the same issue (I totally forgot to disable them in the first term, savegame can be loaded without any but the base mod)

[boskid]

I was hoping for something more interesting but this was already being reported multiple times in different contexts. Line on the splitter output was kept active and so it updated first, then the line downstream of it started to move requesting all the transport lines upstream to update but the right output of a splitter was already updated so it did not move and the gap was created. Fixing this is not easy without performance impact or more complex logic (that would be failing in case of a circular belts). I am moving this to won't fix.

Ref 62553