Member Export outputs duplicates when using pmpro_set_max_user_per_export_loop filter

[JarrydLong]

Describe the bug
Using the pmpro_set_max_user_per_export_loop filter to reduce the number of users per export loop results in the export containing duplicates of a member. By the looks of it the start of the next loop includes a user from the previous query/loop.

To Reproduce

I've tested this based on a small number of members however this grows into thousands of records on a site with 5000 members for example (nearly double).

My base of users were 8 users:

My export using the default pmpro_set_max_user_per_export_loop = 2000 resulted in 8 records exported. No duplicates.

I then set the pmpro_set_max_user_per_export_loop = 2 which resulted in 11 records being exported

Just to be sure, I changed pmpro_set_max_user_per_export_loop = 1 which resulted in 17 records

Expected behavior
We shouldn't be seeing duplicates. Reducing the pmpro_set_max_user_per_export_loop helps with different server limits so the feature is helpful.

Isolating the problem (mark completed items with an [x]):

• I have deactivated other plugins and confirmed this bug occurs when only Paid Memberships Pro plugin is active.
• This bug happens with a default WordPress theme active, or Memberlite.
• I can reproduce this bug consistently using the steps above.

WordPress Environment

PMPro 3.3.2