LCA's bidding pay only have some protection but as far as I know FLEX do not have any reduction under the CBA.

b. When assigned flight duties in an aircraft (other than fl y
days), the maximum number of duty days on an LCA’s
schedule shall be determined by dividing his pay only BLG/
RLG (plus up to 5 days of carryover if bid) by 6 CH rounded
to the nearest whole number. Beginning with the January
2008 bid period, his pay only BLG/RLG shall be divided by
6:24, but the minimum number of duty days shall be 12 (15
in 5 week bid period).