Error in console - children not defined

[dineshm72]

Describe the bug
I am having many issues with Next Up not working quite right.
1- It doesn't always close the current char sheet
2- It doesn't consistently place the newly opened char sheets (this might be a difference between PCs and NPCs)

I see some errors in the console which may be relevant, but I'm not sure. Every time I advance the tracker, I get an error like this:

These errors occur with just Next Up, FTC, and some libraries I have enabled all the time just to make FTC work better. It seems unlikely any are contributing to the issue.

Here are my settings:

To Reproduce
Steps to reproduce the behavior:

1. Start a combat with 2 or more tokens
2. Hit the next combatant button repeatedly, the sheets don't always open in the desired location (sometimes they are centered-ish), and they don't always close after their turn is over (it's possible each is closing 2 turns after they finish? I am not certain.)

Expected behavior
As above.

Screenshots
If applicable, add screenshots to help explain your problem.

hit next:

hit next again:

hit next again (I moved this one slightly so you can see the old one is still there, underneath the new one):

Environment:

• OS: win
• Browser chrome
• Foundry Version 10.291
• Module Version 0.1.14
• All Modules Disabled: mostly
• Module List if no: FTC, some libraries