Why is patch appending the instrument type to the label?

I have twenty identical instruments patched to various addresses.  Four of these have the instrument type appended to whatever label I type and I can't get rid of it by changing to a different type.  It still appends the (old) type name in [brackets] to the label. 

I can make it go away by patching to a null address and then patching the address back.  I don't know how it got appended to begin with and I don't know why it goes away with changing the address.

It's no longer a problem, but I am interested in what caused the label mod to begin with and why it went away.  I presume someone must have thought that behavior useful and would be interested to know why.

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