Ninjago City Docks instructions error?

[badbob001]

I just finished building 70657 Ninjago City Docks and noticed one build step that made no sense.

In step 510, there are these two 1x1 pink round plates:

 

In step 514, a stack of two 1x2 plates are put next to the previous pink round plates.

 

Finally in step 525, the center roof piece is placed on top of the stack of 1x2 plates.

So what is the purpose of the two pink 1x1 round plates if nothing is resting on them? It's not decorative since they are completely hidden. Could this be just a mistake in the design?

With these large sets, I suspect mistakes are possible. Are there other sets that would have steps that had no purpose?

Edited June 3, 2020 by badbob001

[Lyichir]

It's not really an error, since the parts aren't needed elsewhere and don't interfere in any way with the build. If I had to guess, I'd assume that they were there as a sort of marker to help you tell which side of the otherwise largely symmetrical roof build is which, for when you attach parts like the peak of the roof that are meant to face a specific direction. Having brightly colored parts there could help reduce confusion if you were trying to attach that roof section facing the wrong way and couldn't figure out why it wouldn't fit right, since they would make for an obvious difference between the way you built it and the way it is in the instructions (moreso than the black plates versus black brick on the left and right sides of the build, which might not be immediately obvious if they were on the wrong sides).

It's also possible that it's some sort of easter egg the designer put in. Lego easter eggs are sometimes obvious but there are many that are more subtle—such as designers adding plates in the colors of their national flag to the interior of the build. So it could be some sort of obscure inside reference or joke. But I'd sooner bet that it's meant to reduce confusion in the build process.

[Lucarex]

Yep it's not an error but I think some sort of marker (or fallen petals) related to the pink Sakura "balloon" on the opposite side of the roof.