Has Maccas changed their f4ozen coke?

Over the past few weeks i, along with my kids, have commented that the frozen cokes taste different.

Today i got 2 medium frozen cokes several hours apart from different mcdonalds.

The first was fine. Looked and tasted as expected.

The 2nd one is what i have been experiencing the past few weeks. It is much sweeter, has a cola after taste, but does not taste like a normal frozen coke. I also think the colour is lighter but without a direct comparison this could be my eyes playing tricks on me.

Has anyone else noticed a difference?