Song order inside a playlist changes in my iphone

So this frustrates me to no end, and I can't believe it wasn't caught as a glaring feature miss by Apple QA:

Here is the description of the problem:

- I create a smart playlist (My Purchased Songs)

- In iTunes on my Mac, I ensure that the order of songs is listed by Puchased Date

- Then, I sync. my iPhone 6s Plus through iTunes.

- I see the playlist on my iPhone.

And lo!

The song order has changed to some order (sometimes Alphabetical by Artist name) that I had NOT chosen!

I go back to iTunes and even view the order of songs in the playlist in my iPhone inside iTunes and it seems ok. But, when I use the Music App., the playlist song order is completely changed!!

I have searched online and in the end, without any success - have resorted to checking over here for assistance. Apparently, this is a long standing issue!!!

HELP!!

Thanks,

Vinayak