The IRS has said in conferences that they believe letting having the employer receive funds from the plan and then writing the check for a distribution is unacceptable.
That being said, some employers have done it although the rationalization on its acceptability is a bit murky.
There was a temporary regulation that implied this was permissible. See Q&A 16 in https://www.ecfr.gov/current/title-26/section-35.3405-1T (which was "reserved" when the regulation became final).
Some practitioners felt this Q&A made it acceptable for the employer to be involved with making both the distribution, while others felt that this Q&A made it acceptable only for the employer to submit the tax withholding.
Some practitioners took the stance on the question of whether there was a prohibited transaction is it would not be if and only if the employer did not benefit from having had the funds pass through an employer's account. Those who took that stance cautioned employers to hold the cash for the least amount time it took to issue the distribution, and to not put the funds in an account that earned interest.
Treasury 31.3495(c)-1 Withholding on eligible rollover distributions; questions and answers Q&A 5 answers:
Q-5: May the plan administrator shift the withholding responsibility to the payor and, if so, how?
A-5: Yes. The plan administrator may shift the withholding responsibility to the payor by following the procedures set forth in § 35.3405-1, Q&A E-2 through E-5 of this chapter (relating to elective withholding on pensions, annuities and certain other deferred income) with appropriate adjustments, including the plan administrator's identification of amounts that constitute required minimum distributions.
Prudence says do not involve the employer in writing distribution checks. Should circumstances result in the employer receiving and depositing a check in an employer's account, then the employer should as quickly as possible write the check to the participant or to the trustee/custodian who routinely issues distribution checks, and the employer should document all of the circumstances, the actions taken to have the distribution issued, and if needed, any steps taken to give up any interest earned on the amount while in the funds were in the employer's account.