Thoroughly tested on version 1.4.3 with the M2HB HMG emplacement but all FOB HMGs suffer from similar bugs. Default keys were used (C for view switch and right-click for zoom/ADS).
For clarity purposes, the default camera (the one where you are aligned with the sights) will be called CAM1, the second one (where you see the weapon from above and further back) will be called CAM2.
Bug 1: After entering the weapon (and waiting till it works), pressing C once does nothing. You have to press it twice to switch from CAM1 to CAM2. This specific issue only happens when you first enter the weapon. Afterwards, it only takes one press to switch from CAM1 to CAM2 until you exit and re-enter the weapon, causing the bug to occur again.
Bug 2: After switching to CAM2, it always takes two C presses to switch back to CAM1. As if a "CAM3" that is the exact same as CAM2 existed and we were forced to switch through it every time.
Bug 3: Right-clicking when in CAM1 zooms the camera forward (not a bug). However, right-clicking in CAM2 (the first one, not "CAM3" from the above bug - right-clicking after pressing C when already in CAM2 does nothing) switches you back to CAM1 and you are now unable to zoom forward in CAM1. You have to press C 3 times to switch out of that bugged CAM1 to CAM2, then twice to go from CAM2 to CAM1 (due to bug 2). After those FIVE C button presses, you are back to CAM1 and can zoom again there.
Not sure if I explained it all clearly. In short, it's fucked to hell and back and I constantly see new players who are puzzled with these fixed HMGs due to the bugged cameras/viewpoints.
For clarity purposes, the default camera (the one where you are aligned with the sights) will be called CAM1, the second one (where you see the weapon from above and further back) will be called CAM2.
Bug 1: After entering the weapon (and waiting till it works), pressing C once does nothing. You have to press it twice to switch from CAM1 to CAM2. This specific issue only happens when you first enter the weapon. Afterwards, it only takes one press to switch from CAM1 to CAM2 until you exit and re-enter the weapon, causing the bug to occur again.
Bug 2: After switching to CAM2, it always takes two C presses to switch back to CAM1. As if a "CAM3" that is the exact same as CAM2 existed and we were forced to switch through it every time.
Bug 3: Right-clicking when in CAM1 zooms the camera forward (not a bug). However, right-clicking in CAM2 (the first one, not "CAM3" from the above bug - right-clicking after pressing C when already in CAM2 does nothing) switches you back to CAM1 and you are now unable to zoom forward in CAM1. You have to press C 3 times to switch out of that bugged CAM1 to CAM2, then twice to go from CAM2 to CAM1 (due to bug 2). After those FIVE C button presses, you are back to CAM1 and can zoom again there.
Not sure if I explained it all clearly. In short, it's fucked to hell and back and I constantly see new players who are puzzled with these fixed HMGs due to the bugged cameras/viewpoints.