Membership plugin losing members

I run a membership site for a small organization. We are using one of the paid WP plugins available (WooCommerce Membership by RightPress). Recently I have found members are losing their membership record in the plugin, and the dates for “membership began” and “membership expiration” are also disappearing from their User record.

There seems to be no pattern to the dates lost (that is, not the last added, not the earliest, etc) except that they are not current in their membership.

I have double checked woo commerce settings so there is no chance of inactive members being deleted.

It’s a fairly recent occurrence, but 50 names last month and 50 this month isn’t good.

Any ideas what could be going on?