You can't use the # in combination with text. Normally bold should open and closed with # like italic use.

_ text  _

But for bold just one # is enough. How to fix that bold use 2 #:

# bold #

The # is not meant for bold.

It is used for headings

Heading 1

Heading 2

Heading 3

Heading 4

Heading 5

Heading 6

#Heading 1

##Heading 2

###Heading 3

####Heading 4

#####Heading 5

######Heading 6

The # is not meant for bold.

It is used for headings
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Ha ha thanks. Sorry my mistake.
I changed this now in my editor.js and marked.js.