Error + CTD from bed assignment panel

[okradonkey]

Mods loaded: Harmony, Core, 4M

1. Get two colonists in a relationship: Lover or spouse
2. Build a double bed (or double sleeping spot, royal bed, double bedroll)
3. Select the bed and click the Set Owner button
4. Assign one of the lovers
5. Next to the assigned lover, click the broken heart icon
6. Crash to desktop with the following error:

Exception filling window for RimWorld.Dialog_AssignBuildingOwner: System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper dynamic-method) RimWorld.Dialog_AssignBuildingOwner.DMD<DMD<DoWindowContents_Patch0>?559715712::DoWindowContents_Patch0>(RimWorld.Dialog_AssignBuildingOwner,UnityEngine.Rect)
  at Verse.Window.InnerWindowOnGUI (System.Int32 x) [0x00165] in <c8e8d421567e4ee5864626a429a27a37>:0 

Notes:

• The broken heart's tooltip appears correctly, naming the otherPawn.
• If the previously assigned bed does NOT have SleepingSlotsCount >= 2, the error does not occur, so everything seems fine through line 410.
• I believe the problem must be in line 412.
• I'm not quite able to figure out the solution...

Thank you!