When the orgmode package loads, it folds in unrelated files

I have a custom file type with my own .sublime-syntax file. When I load the orgmode package with Package Control->Enable package (after disabling it), or restart the editor, orgmode will collapse some sections in this file. Seems like a bug to me. Can I disable this somewhere? Can I tell orgmode to ignore any file that's not a .org file? Seems to me like this should be the default.

Reproduce the issue by disabling and re-enabling the orgmode package through Package Control, or by restarting the editor, with a custom file type using its own .sublime-syntax file. Trace the package-loading and folding behavior to determine why non-.org files are affected; done means unrelated files remain unfolded while .org files retain their expected behavior.

Written by the indexing model from the issue text.