When SSL proxy and UTM is enabled in the policy, Youtube videos keep on buffering and will never play.
Under Monitor security packet-drops, "Dropped by UTM:UTM Web-Filtering blocked" logs are seen.

Line   95: 12:46:48.085656:LSYS-ID-00 x.x.x.x/53186-->y.y.y.y/443;tcp,ipid-62646,.local..0,Dropped by UTM:UTM Web-Filtering blocked
Line   96: 12:46:48.085690:LSYS-ID-00 x.x.x.x/53185-->y.y.y.y/443;tcp,ipid-63414,.local..0,Dropped by UTM:UTM Web-Filtering blocked

Unable to watch Youtube videos.
Issue has been seen only with the SRX 4K version 22.2R3-S1.9

It is addressed in PR1755998, and Engineering has committed fix in versions: junos:22.2R3-S3 junos:23.4R2

https://prsearch.juniper.net/problemreport/PR1755998