TEXTJOIN on output of array formula does not ignore blanks

[pi]

Hi!

I have the following situation: In a large table I have conditions in column A and values in column B. I want to create a list of those values in B which meet a given condition in column A ("textjoinif"). To do so I basically have TEXTJOIN(", ";TRUE; IF(columnA="example";columnB;"")).

Yet TEXTJOIN does not ignore the blank lines. Why? What can I do to fix it? I want to avoid to clean up in a second step.

Thanks!
pi

 

[pi]

Confusion gets worse I use the TEXTJOIN construct described above in another table where I pull it down along a few hundred lines. The "example" is linked to another column. No it works in some lines and not in others, even if the "example" is the exact same value. So the array formula returns the exact same array, but TEXTJOIN creates different output.