HFSA, grace period, annual contribution limit, and taxable amounts

Does a grace period affect the amount that can be contributed to a HFSA in a year and still not be taxable?  For example: 

2020 HFSA election: $2750

In 2020, you incurred and are reimbursed for $2700 in expenses, so $50 is available for expenses that can be incurred during the grace period in 2021 and reimbursed and not forfeited.  

2021 HFSA election: $2750

In 2021, you incur and are reimbursed for $2800 in expenses ($50 from 2020 that was used up during the grace period and $2750 from the 2021 election that was used up during 2021).  

Does this mean the $50 is taxable to the employee in 2021 since it exceeds the $2750 annual limit?  I understand this is how it works when the dependent care spending account annual limit ($5000 - I'm ignoring the recent increase for this example) is exceeded but not sure about a HFSA.  (I also know a HFSA carryover is different and the carryover and annual limit are combined and not taxable to the employee.)

Thanks in advance!

<Bump> This unanswered topic needs some love 😄

The grace period for year one coverage does not affect the employee's contribution limit for year two coverage.

The technical rules are in Prop. Treas. Reg. §1.125-1(e).  But more useful is the IRS confirmation in its recent notice addressing the extended grace period option:

IRS Notice 2021-15

https://www.irs.gov/pub/irs-drop/n-21-15.pdf

If an employer adopts the § 214 carryover or the extended period for incurring claims permitted by § 214(c)(1) of the Act, the annual limits under §§ 125(i) and 129(a) apply to amounts contributed to a health FSA or dependent care assistance program for a particular year, and not to amounts reimbursed or otherwise available for reimbursement from a health FSA or dependent care assistance program in a particular plan or calendar year. Thus, unused amounts carried over from prior years or available during an extended period for incurring claims are not taken into account in determining the annual limit applicable for the following year.