I do not think it is a bug, as ofnuts wrote there is no blue in the image. Not unknown with underwater images to be missing a colour.
There is an old gimp script for initial corrections, it is a white balance set up for underwater. This description from the script.
---------
; DESCRIPTION
;; This script acts as a red fitler on diving photos.
;; To launch it, goto the menu <Image>/Script-Fu/Enhance/Diving red filter
;;
;; Basically, create a new layer containing the corrected picture
;; You can adjust the red level (sometimes, green might works better !)
;; and set if the white balance has to be performed...
--------
script attached: unzip put in C:\Users\"yourname"\AppData\Roaming\GIMP\2.10\scripts
Also not a bad idea to up the precision prior to any editing, it might help Image -> Precision say 32 bit floating and linear.
A very quick view of that as an animation. https://i.imgur.com/O0FCNNC.mp4 that also shows a sample point used for color info.
A basis for further editing..
There is an old gimp script for initial corrections, it is a white balance set up for underwater. This description from the script.
---------
; DESCRIPTION
;; This script acts as a red fitler on diving photos.
;; To launch it, goto the menu <Image>/Script-Fu/Enhance/Diving red filter
;;
;; Basically, create a new layer containing the corrected picture
;; You can adjust the red level (sometimes, green might works better !)
;; and set if the white balance has to be performed...
--------
script attached: unzip put in C:\Users\"yourname"\AppData\Roaming\GIMP\2.10\scripts
Also not a bad idea to up the precision prior to any editing, it might help Image -> Precision say 32 bit floating and linear.
A very quick view of that as an animation. https://i.imgur.com/O0FCNNC.mp4 that also shows a sample point used for color info.
A basis for further editing..