The same problem will occur with the spade anchor (or any concave shaped one). The problem is that these designs really scoop into the bottom. That is a good thing for holding, but in very sticky clay/mud, the ball of goop doesn't fall off, or is able to be pushed off by new bottom, when the anchor tries to reset. BTW, the fortress anchor does the same thing in those conditions - it won't reset either. And if the mud is that goopy, the delta and cqr just plows on through without holding. So if you are in Back Creek Annapolis, or a few of the other places with that kind of bottom, you set two anchors in different directions or hope to not get a violent and instant 180* wind shift. Or hope to get lucky.

However, heavy grass can be a problem with resetting due to the roll bar (and kicked up back flukes on the rocna). Here, the bottom would like to slide off easily, but the roll bar blocks its ability. The spade works better in this regard, but doesn't set as readily in heavy weed as the rocna. BTW, we own both a rocna and a spade.

The roll bar is quite necessary for the anchor to set. I have purposely dropped ours backwards and upside down and watched it set and there are definitely setting situations for which the roll bar is required. If it wasn't necessary, rocna and others (manson, buegel) would have done away with it. Spade, ultra and the like use weighted tips to provide unstable attitudes. Raya, sword and the like mount their shafts at the tip of the blade to provide instability in non-setting attitudes.

Ford would probably refuse to respond to a request to cut off part of their suspension to increase a car's clearance to get it over someone's raised lip garage. I wouldn't bang on rocna for doing the same. If the roll bar doesn't fit, you have several other very good choices in modern anchors that are equal in performance to the rocna - raya, spade, ultra for example (Craig, don't bother to respond to that statement - each of those anchors are so vastly better in performance than a cqr that quibbling over their performance vs rocna is splitting a very fine hair).

Mark