Vanguard should have a 1099 that including the dividends from your TRowePrice fund if this was a taxable account. If it was an IRA, there will be no 1099. I would call them up and ask if you cannot find on the web site.
You hint that this fund is held in a non-taxable account, so you should not get 1099. But then one wonders, why do you have a tax-exempt bond fund in a non-taxable account? Or is there a miscommunication here?
It's all about market timing, uh, I mean rebalancing, uh, I mean opportunistic rebalancing, uh, I mean short-term opportunistic rebalancing due to a short-term change in one's asset allocation.