Why does memory keep rising in the editor?

This apparently was a bug fixed in 4.11? But I am on 4.25!
I start at around 3.7Gb when I launch. Then 4.8Gb when I open my scene.
And it gradually keeps rising without me adding more assets.

And I also get an ‘Out of video memory error’ when I try and save the current scene under a new name, followed by a crash.
To get around this I discovered if I simply hide my landscape before doing a ‘Save Current as’ I don’t get the error.

So I am a relative novice and have a lot to learn but don’t see why this is happening?
I have a dozen or so looping 4 and 8k flipbook animations.

Can someone tell me, does the total memory footprint of your textures play a part?
I have several 8k textures.
And what about mipmaps. Does enabling mipmaps on your textures have any impact on the memory footprint?

Thanks in advance for any replies!

Crash is common with ue. larger video memory does help, but eventually it will crash on any pc. If it is for game use smaller texutres (personally I use 4k max). Reuse same textures and use texture tiling. Base on circumstance stick with just diffuse and normal for some materials. Use micro/macro variation and vetex painting to bring variation. use virtual texures where you can. Look into mipmap lod bias.