NSF response: Please see question #5 in this NSF document: Frequently Asked Questions Regarding Current and Pending Support June 28, 2021
This will address your questions. The text of the answer to question 5 is included below.
"Is mentoring of a trainee an example of a time commitment that must be reported in current and pending support? There is a difference between a time commitment and an activity that takes time. Should the latter be reported in current and pending support?
An individual need not identify any mentoring activities in their current and pending support submission that take place as part of their regular appointment at the proposing organization. If an individual, however, receives in-kind support either directly or through their organization from an external source to support mentoring of undergraduate or graduate students, that in-kind support, including the time associated with such mentoring, should be identified in the individual’s current and pending support submission."