Problem with scenery inside containers

I have a bunk. The bunk is a supporter (or surface in Adventuron parlance). I decided to add a pillow, sheets and blanket to the bunk. You can examine them, but you can’t get them, so I made them scenery. I added a response for each of these three objects so that if you tried to get an object, it gave you a reason why you couldn’t get it.

There’s just one problem. When you try to get one of these objects, it does not print my custom message, but prints the default “You can’t take that.” message that you get for all scenery. However, with normal scenery, you can override the message. With scenery in a container or on a surface, you apparently can’t. Is that a bug? It sure sounds like it.

To overcome this problem, I changed these three objects from scenery to object and now I get my custom message for two of them.

When I try to GET SHEET (singular), I get a response saying “You look around but can’t see any rubber anywhere.” What the @$#%?

This occurs because I have a sheet of rubber elsewhere in the game. It is not in scope. It is not in the same room. In fact, it hasn’t even been created! I tried adding "get sheet" (singular) to my match statement, but that didn’t help. I tried adding : match "get _" {: disambiguate_s1 "beside";} at the beginning of the on_pre_command section and that didn’t work. Ditto for : disambiguate_s1 "present";. I tried changing the object ID for the sheet of rubber from sheet_rubber to just rubber and that didn’t work. The primary noun for the rubber is ‘rubber’, not ‘sheet’. sheet is not defined in the vocabulary{} section. The sheet of rubber is defined as:
rubber : object "a sheet of rubber" {experimental_matching_text_sequences = ["sheet of rubber", "sheet", "rubber"]}

So how the hell do I get GET SHEET to be understood as GET SHEET and not GET RUBBER?