Let's quote the relevant documentation here:

API: "an 8-bit globally-paletted GIF"
Chatlog: "does not define a global 256 color palette"

So JJ2+ is detecting that your GIF files have color tables, just not color tables that it's excited to work with. Specifically:

• globe: seems fine
• spr_tenna_freakout: the color table is 4 bits, not 8, and has only 16 colors, not 256.
• consider: the color table is 6 bits, not 8, and has only 64 colors, not 256.
• 1078739080889761993: although there is a global color table of the proper size, at least one individual gif frame defines its own unique color table, so the gif can't be loaded with a single consistent palette.