I'm using custom admin columns Version 188.8.131.52
and I've just noticed that a setup that was previously working fine now has the bulk action checkboxes missing on any admin page I've customised with the plugin.
I've done a full reset and each time I make a change to a post-type's columns, the change happens, but the bulk action checkbox also disappears.
The only way to then get it back is to do another full reset of the plugin.
Hope that helps. Thanks.