WowAce

I use the blizzard UI "Use Raid style Party frames" option and have disabled parties in SUF. Sometimes it will make the group disappear completely making it look like I'm not in a group. I can still see party chat and even leave party by right clicking on portrait but my group will randomly appear and disappear  while playing. This issue can be resolved by disabling SUF. I am running the release version 1.6.3 I noticed the issue began to really present it self after the release of 7.1.5 TYIA and if I could make a mention since I play a lock would there be a way to enable there Soul Effigy icon on the player portrait like the default frames provide. This icon allows the player to dismiss the effigy w/o this option you can remain in combat w/ Odyn when taking a talent making corruption permanent up to 10 mins for the effigy ti disappear on its own. Again TYIA have a great day

I am also having this exact problem, sometimes I have to log off the game then back on to get them to reappear. So annoying!

Same issue here, using the wow raid style party frames, I do have Raid Frame indicators (extra controls for the WoW raid frames) but after toggling this and many other addons off, the dissapearing Party frames seems to be tied to SF.

I've (thankfully) not had any issues with raid frames yet so hoping this is just isolated to parties and can be fixed. It makes healing dungeons interesting to say the least!