Happening with en route waypoints also:
EGSS CLN9R CLN M84 KONAN DCT KOK DCT CIV DCT SUTAL DCT GTQ DCT BAMEV DCT BLM BLM3G LSZH
During the SID, given a DCT SUTAL and had the same drift behaviour. Yes, no airway segments there however wasn't only SID/STAR in FMC