New Table Import Feature -- Error when using WOTC official D&D Theme extension

Was getting an error using the new table import feature in Fantasy Grounds Classic, version 3.3.12a

Did a lot of troubleshooting and found that the difference between getting the error or not was if I turned on the extension "Theme: D&D - Official"

Just to double check, I just now created a brand new blank campaign with 5e ruleset, and turned on only this theme. No other extensions loaded, no modules loaded.
I went directly to tables, the new table import (the blue circle with white up arrow).

I typed in a name and a simple table -- just four lines, a, b, c, d (see screenshot for what I'm entering in the dialog box)

Attachment 41482

and I get the error: "Script Error: [string "campaign/scripts/tableimport.lua"]:228: attempt to index field 'subwindow' (a nil value)"

I get the same error if I also use numbers before the entries, that is
1 a
2 b
3 c
4 d

(with a double space between number and letter).

It does create a table, but gives me the error. If I turn off that extension theme, I do not get the error.

I posted under discord and Moon Wizard directed me to enter in House of Healing forums.
Thank you.

I can reproduce this in Classic; it works as expected in Unity.