@vip_indian , generally agreeing with comments by @Opus 17 ---- just a few points here
1. This seems to be an old thread and I don't know if OP is going find this useful h, however:
2. Need to recognize that RSU ( Restricted Stock Units ) are treated as "delayed" salary/bonus with one or two trigger mechanisms with first being required service length before vesting. Thus Grant is a promise to pay while vesting is delivery of stock at the current valuation ( market or otherwise).
3.Therefore and generally vesting of the promised shares would trigger a taxable income of the active kind i.e. it is subject to FICA regulations. On this I am unclear if OP had already included this in-kind payment / bonus in his filing for the year when vesting took place ( 2019 ? ).
4. Once the stocks are delivered to the grantee, then this is like any other stock owned i.e it is a passive income item -- dividends and any gain/loss on disposition is a taxable earning ( either ordinary or capital). This is as far as the US taxation goes.
5. If the owner of the asset moves abroad ( tax home abroad) and is not a US person ( citizen/Green Card / Resident for tax purposes), the earnings would still be US sourced , owned by a Non-Resident Alien, taxed at the fixed 30% and the broker would be required to withhold federal taxes .
6. This is generally the reason why many tax professional suggest that a a resident for tax purposes , before leaving the USA ( i.e. becoming an NRA ) should go through some planning / pruning of investment accounts. This is because and especially in case of India, the dividend income ( article 10 ), interest income ( article 11) and capital Gains ( article 13 ) may all be taxed by both jurisdictions -- there are some limits ( dividend @15% ) and carve outs, especially for immovable assets. So I would strongly suggest that OP have a discussion with a knowledgeable tax professional or a financial adviser familiar with US-India treaty.
7. As far a CA goes, per publication 1006 and generally in line with IRS view of life, the value of vested shares per period need to be allocated based on the number days that were worked in CA. It is a somewhat contorted view because it assumes that all the tranches of the grant were partially or wholly earned during the work period while in CA -- thus assuring that CA gets a cut even if the beneficial owner left CA and continued to earn time towards vesting.
Bottom line of all the above is that (a) the vesting of the shares / award trigger a W-2 type of earnings based on the FMV of the shares on the date of vesting; (b) Dividends earned thereafter are treated as passive income for NRA and taxed by both jurisdictions ( with limit ); (c) disposition will trigger gain/loss based on basis at vesting and will be taxed by both jurisdictions; (d) tax planning is a good idea in such cases. I am assuming here that the OP did not exercise section 83(f) {??} option to recognize valuation at grant date and that there is still time to do some planning.
I apologize for delay in responding
pk
