The position that the game renders the fishing line changes depending on what aspect ratio the game is being played in. Correct behaviour only occurs with a resolution that has an aspect ratio of ~16:9.

Note: Issue occurs no matter what FOV is set. Screenshots taken at 80 FOV.

What I expected to happen was...:
The fishing line should take the aspect ratio into account when determining its position on screen.

What actually happened was...:
Fishing line is rendered offset to left of the Fishing Rod when playing with an aspect ratio with a lower width, such as 4:3. Fishing line is rendered offset to the right of the Fishing Rod when playing with an aspect ratio with a higher width, such as 21:9. Offset direction is reversed when the Fishing Rod is held in the left hand.

Steps to Reproduce:
1. Use Fishing Rod to throw the line.
2. Change the horizontal size of the window.
3. Notice how the fishing line's location disconnects from the Fishing Rod as the width is changed.

Possibly related to:

1. MC-116379
2. MC-148088
3. MC-109884
4. MC-198777

Also seems to be the actual issue reported in MC-190324 as the linked video's resolution of 1744x1080 has an aspect ratio with a width lower than 16:9 and I was unable to reproduce the issue in a 1920x1080 window.