The 40-basis-point cap shift is worth scrutinizing carefully, and you are right that the promote math amplifies it at your tier more than the IRR headline suggests.
The assumption doing the most work here is whether the 6.2 is market-derived or operator-derived. Those are different things. If the operator pulled recent comp sales in the Stockton submarket and they genuinely transacted at 6.2 or wider, that is a conservative but defensible update. If the number comes from the operator's own read on buyer appetite with no comp support, you are looking at a narrative being built, and the question is what it benefits.
The risk you did not name: a soft reforecast six months before exit sometimes precedes a request to extend the hold. The operator gets more runway, the promote clock resets in some waterfall structures, and the original exit pressure eases. Check your JV agreement for what triggers an extension, who has the right to call it, and whether the hurdle rate resets or accrues through any extension period. That is where the real exposure sits.
On whether this pattern is common: operators do update assumptions as a market approaches, and responsible ones update them in writing before close rather than after. The timing is not inherently suspicious. What matters is whether the update is accompanied by an ask, a proposed change to structure, or a suggestion that a lower bid should be accepted. If it is a standalone update with no attached request, treat it as information and push back with comp data.
Request the actual sale comps the operator used to arrive at 6.2. If they cannot produce three closed transactions in the submarket at that range, the number is a forecast, and forecasts six months before exit deserve scrutiny proportional to what they cost you at the promote split.
What does your JV agreement say about approval rights on the sale price, and does the operator need your sign-off to accept a bid below a floor?