iTunes issue

I know this is not a FCP issue but it has been going on for a very long time and I just paid it no mind,

I use my playlists in iTunes to learn new songs for different bands I perform with. I noticed awhile ago that when I have been working off one playlist a lot, when I go to sync up my iPhone, iPad or iPod often the playlist I have been working off of will come up as both the original title of the play list and then the title again with a 1 after it.
For example...Muddy Waters
Muddy Waters 1
If I look at the MW1, it is the same as the original MW, no changes, no differences.

It is easy enough to uncheck the MW 1 on the summary list of music I have in the iPhone but then when I disconnect the device and just go to my list of playlists that MW 1 is still there. I then click on it and delete it leaving only the original playlist. This all happens all the time. If I went back the next day, it would say MW1 all over again.

Why is this occurring and what, if anything, can I do about it?

Thanks for your time. Glad this discussion site is still up and running...I think

That happens a lot to me, but only with one particular playlist for some reason. It's been happening for a couple of years now I think. I have no idea why. I just delete it each time. I think it happens when I add new songs to a playlist. I then get a 1 version of said playlist with the new songs added while the original is unmodified. It's very difficult sometimes adding new songs to my iPhone. It's a gamble if they copy or not.