Some of my roses look like this, they are "stuck" in this stage, 3 or 4 different cultivars are in this situation, one of which is 'Evelyn' by David Austin (not actually pictured here)
Weather has been good, there is sun, wind, garden cleaned last fall.
Few of theses started exhibiting a bit of a thin layer of white-gray mold (botrytis?) on the peduncle and petals (not exactly in photos as it is not dominant, at least not yet), I am not sure if that is the cause or that is just a concurrent issue with another one, but it does feel like I have seen this before somewhere.
I can't seem to see anything moving inside these half opened buds once I break them in pieces, but you never know.

White on the peduncle could be botrytis or powdery mildew. Very double types require a lot of water and heat to fully open. If it's chilly enough, they may not open properly. Flower thrips can also prevent them from fully opening as they suck the sap from the petals and release sugar water which is sticky and glues the petals together.

"White on the peduncle could be botrytis or powdery mildew"
It must be one or the other present right now on some of the roses, seems isolated for now, but I am sure it will spread where it can spread. Usually the botrytis manifested as obvious grey mold on other cultivars and not in spring time.

Water may be a potential issue since you mention it for very double types, the soil in this location seem to dry fast when it's sunny as it's exposed to the south, I cant say it was too chill in the recent weeks.

I wonder if trips are a thing here locally, I am not sure if I would be able to see the trips themselves with my eyes, when I broke up some of these buds they seemed quite fine at the base.