Nah! If you see the details of punctuality loss here click here there are wheel slipping instances (not derailments) reported on all types of locos (includes WAP4, WAP7, WCAM3, WCAM2P etc), particularly in the monsoon when the rails are slippery. P5's slips have also occurred in rainy weather only (not regularly, few occasions), but no such instance was reported in the past 1 year.
Presenting you the most amazing wheel slip reported on WAP4 :
{{On April 17, 2015, 12273 HWH NDLS Duronto lost 11 minutes between MMU & CAM due to continuous...
more... wheel slipping due to drizzling weather on a 1:200 gradient. Loco was "HWH WAP4 22402". No loco trouble.}} Just wow! The wheel slip occurred with mere 17 coaches :D
You'll find similar wheel slips reported on other locos too (including WAP7).