Hi Robert, I also received a similar message back, but I believe it's now been logged as an item we are hoping they may change. The issues I've encountered mainly happen in Layouts - If i have a project that has multiple layouts, the layouts often get confused if there are two maps with the same name. Things like the legend items, scale, and just generally what Pro thinks its looking at may change or get mixed up. I've encountered issues where when Pro is closed, and re-opened, it's repathed to another map and my layout is completed bugged out. I think Pro in general has a hard time with things sharing names (which makes sense) if you have two layers in a map and one is symbolized a specific way (say by type for example) and another is just single symbol - Pro seems to be hit or miss on if it can import the symbology from the other layer. I usually end up giving the feature layer in the map an identifier like "_Symbolized" and then it can recognize them as two separate items.
I'd like to mention i think it's ALWAYS best practice to have your maps/items/layouts be named uniquely and am always doing this as my main workflow, however somethings things get missed, or we have a new person working on a project who may not yet but used to a workflow, and all their work is lost. Definitely best practices can prevent this, but I think having Pro tell me "You cant use that name", similar to how it doesn't let you use special characters when renaming a map, would save a lot of headache.
