That is... Really strange. Factorio shouldn't care about changelogs being janky. It just doesn't display them. Mine seems to be busted somehow, though - seems I forgot to verify before uploading. I'll get it fixed by the top of the hour, and hope that fixes your issue.
edit
Yeah, my changelog was busted in four places: 133, 136, 137, 138. Notepad++ likes to auto-place leading tabs after rows with four leading spaces, and I guess I didn't catch all of them. My bad, should be fixed in 1.3.1. It's still updating, so give it 10-15 minutes. I think my ISP's upload speed is pretty poor.
As to why this is happening... I have no idea. Do you maybe have a mod which tries to do something special with other mods' changelogs? Only thing I can figure, because Factorio proper does not throw errors for those reasons.