Dear Pramod Kadam,
Thank You for Your post and for Your involvement in solving this issue. Below You will find my answers for Your questions:
1. This issue happened only with this model, but it was connected not only exactly with this single model but also with copies (I saved this model with different names in separate files). I have never faced this issue with other models created in Fusion 360.
2. There are a few operations which makes me wondering is could be the reason of this issue:
a) There was a version of this file (I can still find it in the history I suppose) where I deleted many items: unwanted construction surfaces and unwanted sketches - it was about 100 items. I'm wondering is this operation made my file unstable.
b) This file I've started to create in previous update and have been continue in last update.
c) This model is only one I have noticed to loose "appearance" (I mean wood appearance assigned to a few parts is permanently changed to dark steel appearance after reloading or changing visibility of a parts). Please have a look topic: "Model is permanently loosing material appearance after last update" placed 08-08-2021 on the forum.
d) This model is only one I noticed to look very bad with shaded look on a drawing. Please see the subject "Why front view of a shading object looks so ugly on a drawing" placed 04-08-2021.
e) The another operation which can be reason of this issue is saving both of the files (3d model and drawing). I noticed the issue happened after when I was saving both files (model and drawing) quite often (2-3 times per 10 minutes). It's a Irony because I wanted to prevent this issue in this way. It' s good also to ask You why 3d model is saving automatically just after placing the part into drawing? For example It happens when I change a visibility of single parts and put it into drawing. I noticed that I have 20 version of model more just after creating a few sheets of drawing. So the conclusion is that maybe automatic saving and manual saving of drawing caused the issue when are made in the same time in some cases.
f) Sometimes the information appears:

It appears when Fusion 360 is minimized or software is not on the top of all windows.
I hope these informations will be helpful. I have also a Hope Your fix will be released soon and solve this issue because right now I really afraid savings. I'm working with my model with "pdf backup files" which is a poor workaround.
Have a nice day
Zbigniew Krysa