I found naother issue in membership 2 pro plugin, I'm sure this should not be the correct planned feature, it is a bug. Let me explain this
Let's say we have two memberships, Membership A without trial period and Memberhsip B with trial period. Both are recurring type.
So if user select the Membership A and do the payment and after 2 days user have to update his memebrship to Membership B.
He is able to change the membership, but the bad thing is, the user is getting trial period of the second membership which he should not.
Same issue you can try by having both the memberships with trial period.