This is a bug that I have found where I do not know which one is the bug, or if it is a bug at all, so sorry if it isn't.
The cracks on the first two stages of an Iron Golem are effected by a spectral arrow and are highlighted and shown, however, the last stage's cracks are not shown.
I do not know if this is a bug, or which one is the bug (The cracks being highlighted or not)
[media]
This was incorrectly closed as a duplicate, but no other report shows different stages, this is the only one that actually shows the bug related to damaged Golems.
(MC-173834 and MC-176932 are reporting intended features.)