Not syncing custom registration fields with BuddyPress xProfile fields

[ipokkel]

Describe the bug When a member checks out and filled in custom registration fields that was set to sync with BuddPress xProfile fields these custom registration fields for Register Helper are not synchronized with the xProfile fields

Related ticket (moderators only): #415557 To Reproduce Steps to reproduce the behavior:

1. Create fields for Register Helper with a buddypress parameter to sync with a BuddyPress xProfile field
2. Check out for a membership level
3. Navigate to the user's BuddyPress Profile page.
4. See error.

Expected behavior Custom registration fields for Register Helper that is set correctly with a buddypress parameter to synchronize successfully with a BuddyPress xProfile field.

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

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

[ipokkel]

https://github.com/strangerstudios/pmpro-buddypress/pull/88 should fix this