Lag when GM moves token with lighting enabled (since last update v4.1.4)

Ran a session last night where all players were experiencing a lot of lag on a map with lighting enabled. If the GM moved a player token, it would move extremely slow on the player view (roughly half a grid space per second). We'd used this same map without any changes last session without issue (previous session was before v4.1.4). There were only the 3 PC tokens on the map, nothing else. Disabling lighting seems to alleviate the issue.

One player was on the local network. I can recreate the issue with the GM and player both on the local network (local LAN connection, not using Cloud brokering). No lag on the GM computer. If the player moves the token it appears to move normally, but if the GM moves the token it updates slowly for the player.

While the player's token is slowly moving around the map, other map operations (e.g. zoom, pan) is delayed and accessing other tabs of the character sheet take roughly 3 seconds to switch between tabs (normally it's instant).

I recreated the issue in a new campaign which I can send in along with recreate steps if wanted.

GM computer:

• Ryzen 7 3800X
• RTX 2080 Super

Player laptop (higher end mobile workstation from 2016):

• Intel Core i7 6820HQ
• nVidia Quadro M2000M

FGU v4.1.4
5e ruleset v2021-06-08
No extensions loaded

Can you set up the campaign with the same scenario you were seeing last night; then zip up the campaign folder and provide the link; as well as steps to which map/tokens affected?

Thanks,
JPG

I sent the zipped campaign to the support-files email. There is a story entry on the hotkey bar with steps to recreate, but they are as follows:

1. Open a GM and Player client. I had originally seen this with two separate PCs (one GM, one player), but it looks like it also happens with 2 instances on same PC (via localhost).
2. Open map "Player Map - Fane of the Night Serpent". Lighting and Line-of-sight are both enabled.
3. Player connects as PC named "Test"
4. On GM client:
   
   1. Share map
   2. Drag player token from location labeled 1->2->3->1 a few times in a continuous motion (i.e. drag in a circle a few times)
5. On Player client:
   
   1. Token will update slowly around the map, moving about a square a second. While this is processing other actions are delayed (e.g. map zoom/pan, character sheet tabs, etc)

I sent a newly created campaign with the minimum content to recreate.

I've found a potential workaround for anyone else who is experiencing this - enable token locking and have the DM move tokens using token lock mode (by holding ALT when starting to move a token). So far this seems to eliminate all of the lag on the player-end when the DM moves tokens (PC or NPC).

Another workaround is to disable lighting altogether.

Thanks for the information. It might help Carl pinpoint the issue, when he comes up for air on the undo re-work.

Regards,
JPG