Markdown: Bullets not indented correctly

I believe that when rendering the following Markdown:

* Main bullet point
  * Sub-point A
  * Sub-point B

...that the sub-points should be rendered as indented. However it appears as:

• Main bullet point

• • Sub-point A
  • Sub-point B

How other services render it:

• On Github 2 spaces are enough to trigger indenting of sub-bullets
• On StackOverflow, a single space is enough
• On BitBucket it seems to require 4 spaces (as the CommonMark standard seems to indicate)

Unfortunately this means that some of our README files appear incorrect and in a confusing manner, where most bullet points are shown at the same level instead of nested.

Since Github flavored markdown (GFM) is very common, is there any chance that BitBucket could render in the same way?