Several will tell you it is not acceptable.
imho it is acceptable
* she didn’t ask for 10 year gc
* the benefit she is seeking applies whether she has a 10 year card, 2 year card, or no card: she is an LPR
* USCIS refuses to schedule appointments for I-551 stamps
I think she should get full use from that card, whether using it showing evidence of authorized presence to attend school, in state tuition, get an unrestricted SS card, a job, a mortgage, REAL ID, travel, visa waiver to Canada, Mexico, DR, etc. I would not use the card to get global entry. I would use the card at a normal kiosk a US port of entry (and some kiosks just use facial recognition).
What she should not do is pretend to be anything else than what she is: a conditional LPR. And so 90 days before the 2 year anniversary of her “resident since” date she should file I-751 to begin her Kafka-esque nightmare. So she should enjoy these 2 years of bliss while she can.
My prediction is that I-90 will never be adjudicated. Hopefully because if they start off by forcing her to send in her 10 year green card, the nightmare begins.