Software Deployment

Yes. Don't. Use a transform if you need to effect changes to an MSI.

Is it strictly ..dont ..or with some precautions , we can if we are in a unavoidable situation!

Well, that's what I generally say: Do NOT unless it's unavoidable. However, I have yet to encounter a situation where I've had to re-package an MSI. Others have, I know - and people I respect, too, so those situations do arise - but even when provoked to the limit, I have managed to avoid it.

As Ian said; it's not recommended, special for vendor MSIs.
If you do capture and MSI you will not be able to use future updates/patches provided by that vendor if you do not reproduce the exact feature/component (& recourse) details.
In most cases it will be enuf to modify your needs through a transform but just have in mind that depending on what you add to the transform it's not certain you will be able to use the future vendor MSI/MSP/MSM either.

I've been in some situations where I had to recapture the MSI.
It can be a bit hard to find out what some custom actions performs from the vendor MSI which you maybe have to reproduce depending on what they do of course.

If you must do this make sure to enter that into the documentation for the package.
Make sure there is no advertise (Darwin Descriptor) info in the newly produced MSI.