Relationships - inconsistency with metadata and wp_podsrel table

[JoryHogeveen]

Describe the bug

Case: We have a group relationship field to another object. Pods stores the group and _pods_group metakey. But also adds some data in the wp_podsrel table. It seems that Pods relies on the latter for displaying any data in WP admin or anywhere, not the actual group metakey.

I'm updating metadata through a PodsForm on the front-end. The actual form is modified a bit to only show certain options but the data send after submit is the same as usual.

Is this a known issue, and if so, is there a workaround? Why and for what is this table used at all?

Expected behavior I would expect that Pods relationships would work fine with just the regular metakeys (group) as well. Perhaps even as a fallback?

Pods Version

2.7.9

WordPress Environment

``` WordPress Version: 4.9.8

PHP Version: 7.2.8-1+ubuntu16.04.1+deb.sury.org+1

MySQL Version: 5.5.5

Server Software: nginx/1.15.0

Your User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36

Session Save Path: /tmp

Session Save Path Exists: Yes

Session Save Path Writeable: Yes

Session Max Lifetime: 1440

Opcode Cache:

Apc: No Memcached: No OPcache: Yes Redis: No Object Cache:

APC: No APCu: No Memcache: No Memcached: Yes Redis: No WPDB Prefix: wp_

WP Multisite Mode: No

WP Memory Limit: 40M

Pods Network-Wide Activated: No

Pods Install Location: /srv/www/motional.io/releases/20181107113620/web/app/plugins/pods/

Pods Tableless Mode Activated: No

Pods Light Mode Activated: No

Currently Active Theme: WellBeingProfile

Currently Active Plugins:

Admin Columns - Members add-on: 1.1 Admin Columns Pro: 4.3.8 Admin Columns Pro - Pods: 1.2 Beaver Builder Plugin (Pro Version): 2.1.6.3 Gravity Forms: 2.3.6 Gravity PDF: 4.5.0 Intercom: 2.6.1 Members: 2.1.0 Menu Icons: 0.11.2 Motional Snippets: 0.1 Notification: 5.2.4 Pods - Custom Content Types and Fields: 2.7.9 Query Monitor: 3.1.1 SendGrid: 1.11.8 Soil: 3.7.3 TablePress: 1.9.1 View Admin As: 1.8.2 WellBeing Profile (Motional): 1.1.3 WP CLI Login Command Server: 1.2 WPS Hide Login: 1.4.5

</details>