My husband had his interview today, and we were sent home with a letter that our case was being held for further review. The officer was very nice, and the interview went well overall. However, he informed us that the reason he was keeping our case open was because it had been some time since he had reviewed a case adjusting status from K1, and he wasn't sure about the validity of the medical examination that was done prior to the consular interview. We submitted the DS-3025 with our original I-485 application which was marked as 'K Visa applicant voluntarily completed vaccination requirements'. The medical examination was also completed long before the one year requirement from when the application was filed, and no class A medical conditions were revealed. We still had the unsealed envelope with us from the examination, since nobody asked for it when my husband entered the US. We gave that to the officer and he put it in our file. I assume the evidence we provided is enough to just wait for that officer to perform his final review and adjudicate our case. Maybe this could be useful for others to inform them that this might happen should they have an interview adjusting from K1. I guess it depends on the knowledge of the officer on whether he will approve you on the spot or not.