Evidence: <Where><Geq> on ID at 5095 (the newest item id 5100 less 5), grouping on PChoice. The counter spelling was tried rather than assumed: Type="Counter": HTTP 200, SERVED (6 row(s)), so Type="Counter" is what answered. collapsed HTTP 200 returned 4 row(s) against a RowLimit of 100, labels {"PChoice":["Alpha","Beta","Delta","Gamma"]}, grouping markers ["PChoice.COUNT.group","PChoice.newgroup","PChoice.groupindex"], first row {"PChoice":"Alpha","PChoice.urlencoded":"%3B%23Alpha%3B%23","PChoice.singleurlencoded":"Alpha","PChoice.COUNT.group":"2","PChoice.newgroup":"1","PChoice.groupindex":"1_","PreviewThumbnailsQualitySets":""}; expanded HTTP 200 returned 6 row(s); the same query with no <GroupBy> returned HTTP 200 with 6 row(s); ViewXml <View><Query><Where><Geq><FieldRef Name="ID"/><Value Type="Counter">5095</Value></Geq></Where><GroupBy Collapse="TRUE"><FieldRef Name="PChoice"/></GroupBy></Query><ViewFields><FieldRef Name="FileLeafRef"/><FieldRef Name="PChoice"/></ViewFields><RowLimit>100</RowLimit></View>. A <GroupBy> on this column is therefore a request this server accepts and acts on, so a refusal of the same shape at full size below is about the size. #480 measured the same composition honoured on the other fixture; it is re-proved here because the column names and the build differ.