Hello,
When a GPL file has extra spaces between numbers, colors are not loaded from a palette correctly. As an example, here is a selection from the Pico 8 extended palette from PICO-8 Secret Palette Palette that has been reformatted.
GIMP Palette
Name: Pico 8 Extended
Columns: 0
# URL: https://lospec.com/palette-list/pico-8-secret-palette
# Colors: 32
0 0 0 000000
29 43 83 1D2B53
126 37 83 7E2553
0 135 81 008751
171 82 54 AB5236
95 87 79 5F574F
This is how it appears in Pro Motion version 8.0.10:
Leading zeroes do not seem to cause a problem:
GIMP Palette
Name: Pico 8 Extended
Columns: 0
# URL: https://lospec.com/palette-list/pico-8-secret-palette
# Colors: 32
000 000 000 000000
029 043 083 1D2B53
126 037 083 7E2553
000 135 081 008751
171 082 054 AB5236
095 087 079 5F574F
The original file from Lospec uses tabs, which do not cause a problem either.
GIMP Palette
0 0 0 000000
29 43 83 1d2b53
126 37 83 7e2553
0 135 81 008751
171 82 54 ab5236
95 87 79 5f574f
Thank you for considering this issue.