Salesforce CPQ Quote Line Editor has infinite load

When utilizing Quote Line Groups in Quotes, all Quote Lines must belong to a Quote Line Group.

If Quote Line Groups are present on a Quote, 'Group Line Items' (SBQQ__LineItemsGrouped__c) needs to be 'true' to display them. If 'Group Line Items'= 'true' and there are Quote Line Groups present where Quote Lines are not tied to a Group, the Quote Line Editor will infinitely load with an error in the browser console, similar to:

Cannot read properties of undefined (reading 'processQuoteLines')

Add the missing Group to the quote lines that currently are not assigned to a group to resolve the behavior.