I was at KLIA a few nights ago and have a few data points for this thread, though YMMV.

While skulking around the Satellite Concourse, the C gates, I noticed that the sign in front of the transfer desk did not display the SQ Golden Goose as an airline serviced by either of the handling agents at that desk. That may not mean anything, though. I did not see another transfer desk for SQ.

I was booked on the last evening SQ run to SIN, connecting onto SQ 026 to JFK with a 65-minute connection time in SIN for separate PNR's. Cooling my heels at the KUL SKL (my Business Class BP for SQ 026 gained me entry despite being in Economy on the KUL-SIN flight), I started to panic when the inbound aircraft still had not pulled in to gate C2 just 45 minutes before scheduled departure. No delays were posted on the board, and the agent at the SKL and at the gate both assured me that there would be no delays. I was incredulous when the Gate Agent said that 15 minutes before scheduled departure given that boarding had not started. Well, that packed 772 was fully boarded and buttoned up in less than 20 minutes, and we pulled away from the gate less than 5 minutes after scheduled depature. Short taxi to the runway and we were off. Landed early at SIN and were at the gate before scheduled arrival. My near-panic had been unnecessary. So for those taking the KUL-SIN shuttles, SQ treats them like a turnaround run just like the pax do.

Delays with inbound aircraft won't concern pax doing a turnaround, but don't wander off from the gate too far. The Golden Goose may be gone by the time you get back.