When closing map there is a very consistent frame time increase that happens every time,

it appears as a two long spikes Example

This does not happen on other UIs like knowledge Example

The initial short spike from opening is expected, but when closing, the knowledge UI shows no spike, whereas closing map the frame time is all over the place

Any idea on why this is?

Speculation: could be reloading or updating any number of things that may have been paused or otherwise interrupted by the world map display.  They have had exploit issues in the past associated with map load/unload behavior, so it makes sense that there is much more going on there.

Is there a reason why you ask?  Some issue rearing its head?

Well I noticed this when moving around LOML, and the consistence of the irregularity was rather intriguing, since the shape is different on a fresh launch (Example) but still very consistent through out. I did wondered whether if it's related to the delayed map close they did some time ago due to that exploit.

It just make the playing experience a bit uncomfortable when the spikes are long (like in the initial post), as it is now it's more tolerable due to the large spike being very short, but I'm not sure what causes the long spikes and when it will come back.