uo_panel_container_base.uf_retrive Error

Hello Tessitura friends!

I wanted to inquire if anyone else has seen this error - I searched the forums, help section and documentation and couldn't find any information about the object in question or the error details. 

This error occurs for me when I  click on the navigation buttons (up or down) to navigate between the radio buttons in the custom tabs. After clicking a button i click on a custom tab and add a line and try to save.  It only occurs if i attempt to add custom tab data (any custom tab) immediately after clicking up or down button and attempting to save. 

I tried to trace the error as well and didn't come up with anything in the trace about what procedure gets called when you click on the up and down arrows. 

I also checked t_app_object and tr_custom_tab and i don't see any glaring red flags. 

Error: 

Unfortunately, an irrecoverable application error has occurred. The application will need to be closed or restarted.

uo_panel_container_base.uf_retrieve. 18 Null object reference at line 18 in function uf_retrieve of object uo_panel_container_base. (2)

I couldn't locate anything about the object uo_panel_container_base.
I couldn't locate anything about the uf_retrieve. 

If anyone has any insight, suggestions or feedback I would be very apprciative. 

Thank you. 
-Lisa Rudnitsky