The seemingly straightforward 90:10 distributionrule they first came up with in 1995 was fatally undercut by later rulings by the regulator itself and by the courts.
That's true even if you sell the shares the day after the distribution from your plan, since the rule requiring you to hold the stock more than one year to qualify for long-term capital gain rates does not apply to NUA stock withdrawn as part of an LSD.
The subsidiary does not recognize gain on the distribution of any appreciated assets to the parent, which is an exception to the general rule of Section 311(b) that treats a corporate distribution of appreciated assets as a sale.
For example, normally when you take a distribution from a 401(k), the employer has to withhold 20% for taxes, but this rule is waived for in-plan conversions.