Surface update slowdown

[BorisGoreta]

I have a problem with a scene which has material update on. When the first frame starts rendering I have noticed that Layout CPU usage goes to 80% for a brief period and then comes to 0 again. This prevents the scene update to update fast. After Octane starts rendering the sequence, LW should not calculate anything, at least not at 80% usage. The material that is being updated just has an image sequence.
If I hit Pause on the Octane preview window immediately when the first frame of the sequence starts rendering and let LW do it's CPU thing at 80% peak usage (lasts for 8 seconds) and then resume rendering, UPDATING SCENE... comes down to 1 second for all remaining frames and CPU usage is low, no more peaks. If I don't do that pause/resume procedure, UPDATING SCENE... is 10 seconds for all frames.