Invalid Figure Field when using API

Coming across this in few different ways when making docs and noticed it raised in the community forum too.

https://community.plot.ly/t/remove-edit-chart-from-embedded-html-graph-made-in-r/1601/2

When using scattercarpet type script below, I kept receiving the error:

Error: Client error: (400) Bad Request Figure field is invalid. Reason: Raw data arrays are not allowed at this endpoint. Use grid references instead. Raw data found at the following paths in the figure [('data', 1, u'y')]

p <- plot_ly(
    type = 'carpet',
    a = c(4, 4, 4, 4.5, 4.5, 4.5, 5, 5, 5, 6, 6, 6),
    b = c(1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3),
    y = c(2, 3.5, 4, 3, 4.5, 5, 5.5, 6.5, 7.5, 8, 8.5, 10),
    aaxis = list(
      tickprefix = 'a = ',
      ticksuffix = 'm',
      smoothing = 1,
      minorgridcount = 9
      ),
    baxis = list(
      tickprefix = 'b = ',
      ticksuffix = 'Pa',
      smoothing = 1,
      minorgridcount = 9
      )
    ) %>%
  add_trace(
    type = 'scattercarpet',
    a = c(4, 4.5, 5, 6),
    b = c(2.5, 2.5, 2.5, 2.5),
    line = list(
      shape = 'spline',
      smoothing = 1,
      color = 'blue'
    )
  )

api_create(p)

Start by reproducing the provided R example with plot_ly(), add_trace(), and api_create(), focusing on the scattercarpet trace and the reported raw-data validation error. Read the API figure validation or serialization path that handles these calls; done means the example is accepted by the API without the invalid Figure field error.