[2.1.9] Power satisfaction flashes yellow for a single tick despite sufficient power generation

[elfakyn]

What did you do?

1. On Gleba, have 2k solar panels, 1.5k accumulators, 48 steam turbines / 24 heat exchangers / 6 heating towers - around 200-300 MW maximum production
2. Also have a significant number of roboports with around 1k robots.
3. Everything is on the same power grid. Consumption is around 120 MW
4. Open the power production panel

What happened?

Every once in a while, the power satisfaction dips to yellow, but still shows 122 / 122 MW, and the production shows 122 / 300 MW or so. This happens for a tick or two at most after which it returns to green.

What did you expect to happen instead? It might be obvious to you, but do it anyway!

I expected satisfaction to remain at 100%.

Does it happen always, once, or sometimes?

It rarely happens. I couldn't replicate this on a smaller save so I'm including the whole save here.

Other notes

Factorio 2.1.9, installed from Steam, experimental branch, Windows 11.

I'm not sure this is a bug. I wonder if it is a particularly obscure quirk related to how power works; I wasn't able to find any references to this behavior either on the forums, on reddit, or on the wiki. I'm reporting it because it would be counterintuitive to me as a player -- if I see yellow in my power satisfaction graph I expect something is insufficient about my power production that I should investigate; but everything appears correct.

I've attached screenshots + log file + save.

[boskid]

Thanks for the report. Issue is now fixed for 2.1.10. It was a weird floating point math error where electric network satisfaction value computed one way was not exactly 1 while individual metrics for primary demand and secondary demand were all saying electric network demand is fully satisifed. I made it such that if all individual categories are fully satisfied (primary demand and secondary demand), then the satisfaction value will report as 1 even if the other method reports value slightly below.

[Haisom]

Ok, glad I wasn't the only one noticing this, it was driving me bonkers! I thought I was doing something wrong.