Unfortunately, my HSA provider is OptumBank, and they don't have a "regular" investment side of the business. To no-one's surprise, the agent whom I spoke to on the phone clearly had no clue at all about tax treatment of HSAs in CA.
On the plus side, I just did the math and as it turns out the conversion happened at a time when the market was low enough that none of my lots in these funds had any actual gains, so it seems like this is not going to have any impact either way (other than bookkeeping -- there were losses, but due to the immediate re-purchase in a different class I assume these would be subject to the wash sale rule).
