This camera bug primarily has to do with "The Joy of Perspective" mod. No matter what other horse mods you have, it will not fix this camera issue. I do not have any of the DLCs so I am not exactly sure what the crossbow issue is--but again, since you are in first-person, I would assume it's an issue with "The Joy of Perspective" mode (some items, like armor, weapons, misc, etc., are invisible in first-person because the mod did not toggle that item to appear in 1st-person.) I think FNIS will only adjust the crossbow in your third-person animation--TJoP has it's own set of animations it uses for first-person, so that might be the culprit. I've tried many ways to get around this problem, but so far it's to either have TJoP on and enjoy some 1st-person immersion, or to have TJoP off and enjoy horse riding and less camera issues. I have found a temporary solution for horses though, but it breaks immersion and is horrid from a gameplay standpoint. If you want to view your horse properly (like the vanilla 3rd-person that is), you will have to turn off TJoP in your mod list (you can uninstall it too, but it shouldn't make too much of a difference--less steps this way). Then you navigate to your "Data/meshes/actors/character/_1stperson" folder and move or rename the "skeleton.nif" (I would just rename it to "_skeleton.nif"). Then load your Skyrim and get on your horse (you may have to enter a cell/room/city wall and return to refresh the camera settings if it doesn't work right away). While on your horse, make a save file and exit back to desktop. Then, re-enable/reinstall TJoP and make sure that the previous "skeleton.nif" is in the proper folder and correctly named. Now relaunch Skyrim and load your save file. You can now dismount and remount your horse without any camera glitching. However, the bad news... this fix is only temporary. While you get to ride your horse glitch-free, the glitch may and will return at some point. I discovered when you exit a cell and re-enter, the camera more often than not will glitch back when you remount the horse. Another common glitch is that even though you fixed it for one mount/horse, the process has to be done again to fix another mount/horse--so if you own multiple mounts, you'll need to go through the process again, and again. But even that is not guaranteed to fix your mount camera as every time you reload your save with TJoP re-enabled and exit a cell, it'll reset the camera--so in effect, if you fix the camera for one mount, the other mount could have it's camera reset due to exiting the cell to fix the current mount's camera... and you know you can't be on multiple mounts at once--not even the Dovahkiin is that talented! So if you don't want to go through all of that mess, you can either settle with a broken first-person and horse-riding, or preserve the vanilla horse-riding and first person. I settled with the broken method as I understand TJoP mod is still in beta phase and hopefully it'll get better, and hopefully the devs of the mod will find a better solution to the horse camera than the not-100%-guaranteed fix. I usually transition between first and third person often and avoid any mount riding until that camera issue is fixed. Hope this helps! --- Also to note, a little history: The horses in Skyrim did not have mounted combat initially in the early release of the game. Somewhere in the development of Skyrim, after the initial release, Bethesda started patching their game and eventually added mounted combat. Once they did, I assume they had to alter the camera in such a way to make that possible. So for the modders who made custom camera mods for horses, their mods suddenly became incompatible (and I think TJoP mod was one of those mods). There were values you could tweak in the "Skyrim.ini" file that would alter the position and rotation of the horse camera, but those values are now defunct because of the later patches of Skyrim. So if different values control the camera while on horseback, modders will need to figure out what those values are. Else, if the mounted camera is the character camera, then altering it would be an issue as it will also alter the character's camera as well... I'm not exactly sure which is the issue, but I am optimistic that there will be a fix for it later down the line.
