After my tsting, in the full screen and wider small window states of Win11 or Win10, the first-person rendering of "attachable" is normal. However, in the taller small window states, the model that leans to the right will lean even more to the right, and the model that leans to the left will lean even more to the left. 

The issue I am reporting is an offset anomaly of the model rendering in the Android app of the same package. This is mainly related to different platforms and can be consistently reproduced. I welcome the official staff to contact me through the email associated with my Jira account so that I can privately provide the resource package for testing. The comparison experiment of different window resolutions is just a speculation that it is related to the resolution, and it is not the main focus of this report.

However, when running the same package on Android's MCBE, there will be an abnormal offset, specifically in the top right corner.

I want to remind you that the following description may not be accurate. In my description, it is as if the center of the first-person perspective has been shifted to the top right.

One of my friends said that this issue only occurs with "attachable", and adding rendering to the player entity will not have this problem.

Another friend of mine said that this anomaly also occurs on the player entity.

However, it is true that we do not have a means to adapt model animations based on screen ratios (or there is no existing official tutorial to reference).