Applying bold, italics and strikethrough simultaneously is handled inconsistently

[cometeer]

When using ~~*** or ***~~ to open and close a piece of text all three modifiers are applied correctly.
When using *~~** or **~~* to open and close a piece of text, only the most inner modifier is applied and the other characters are rendered as text.
However, given this sample: *~~**italicstrikebold** italicstric~~ italic* all modifiers are applied as expected.