the bottom picture is it just pooping totally okay. Heres my rule of thumb for torches and I watch my torch tank like a hawk when I am home, It is the tank closest to me from where I sit and I have to walk by it to go anywhere in the house. If a torch looks unhappy I make a little mental note of the torch and the time. by unhappy I mean every other coral is out and inflated and it is closed with the tentacles pulled in and you can see the teeth on the rim. thats worst case unhappy. anyway I just chill out for an hour or so and check it again. if no change I will, dependant on which coral, give it another 30 minutes or start testing for ones that just do not close up that much. If in 30 minutes it is still off I start with my apex if I haven't done so and work backwards until I am done manually testing. i always start with Po4, No3 then do mag,alk,calc. Mag plays a big role with happy euphyllia.
Waynerock and fishko said it best and it can worry some. I have seen them so far retracted they look like theyve bailed out, yet they come back out all happy and beautiful. My Aussie Gold HG is notorious for doing this. I like to take that time to investigate how far along the splitting process is and how fast it is doing so with pics to compare if possible. As to the why they do this and other really strange behavior, I wish I knew and I do not think anyone really does from a scientifically provable viewpoint.
To directly answer your question I would first start with any nipping fish. If you have a nipper then you have an issue that is directly ******* that torch off. Torches do not like to have their tentacles chewed off. it goes without saying. next maybe it is just me but I cannot see the white you speak of in the tentacles. but if that is happening it is more than likely because of a change in the zooxanthellae it has, or has too many of. Thats is my opinion though I am not a scientist. But if there has been NO changes to lighting or light schedule in the past 6 months and you are offering a stable environment then that would be the next logical choice for bleaching.
are you getting good growth? what are your parameters and length of light schedule? Have you ran a Par meter in your tank? all questions that need to be answered before any honest evaluation or opinion can or should be given. So far I have only heard or seen 1 real issue with yours and that is the fish chewing on it.
I keep my tank at or close to I do not chase
Po4 .05ppm
No3 5-10ppm
PH 8.35-8.5
mag 1450 ppm
alk 10.25 DKH
calc 450ppm
Sal 35ppt
temp 77-78 dependent on time of year
I run an ATI 8 bulb dimmable fixture with 2 XHOs for 13.5 hours a day with both ramping up and down maximum PAR 275 minimum Par 125