Nothing unusual here.
SQ in the past has used slack periods to get rid of those, for whatever perceived reasons, they consider not team players.
In early 1980 when fuel prices spiked, the 707 fleet was reduced (in 1981 eliminated) and a few Captains, who marched to their own music, were dismissed.
In addition, several others were not offered positions on the B747.
Several of these folks gave a really hard time to many local First Officers, for reasons known only to themselves.
Could never understand why as almost all of these same First Officers moved onto the 707 (and 727) directly from light aircraft, and did a fine job.