Evidence: 3 order(s) of the same three columns, each sent collapsed. Unindexed: LVChoice > LVNumber > LVDate: HTTP 500 rejected, 0 row(s), dimensions [] {"odata.error":{"code":"-2147467259, Microsoft.SharePoint.SPException","message":{"lang":"en-US","value":"Cannot complete this action.\n\nPlease try again."}}}; LVDate > LVNumber > LVChoice: HTTP 500 rejected, 0 row(s), dimensions [] {"odata.error":{"code":"-2147467259, Microsoft.SharePoint.SPException","message":{"lang":"en-US","value":"Cannot complete this action.\n\nPlease try again."}}}; LVNumber > LVChoice > LVDate: HTTP 500 rejected, 0 row(s), dimensions [] {"odata.error":{"code":"-2147467259, Microsoft.SharePoint.SPException","message":{"lang":"en-US","value":"Cannot complete this action.\n\nPlease try again."}}}. Indexed: not taken. The indexed half was not reached, so this row is about the unindexed legs alone.. Every order was given the same class of answer, so nothing below turns on which order the primary question used, and a view that groups on these three columns cannot be rescued by reordering them.