I was able to confirm that it is indeed the k_hjuh_dialog.dlg file from this mod that is causing the error. After I removed that file from my override folder the conversation played out as it normally does for a male character. I also noticed that the conversation option "Why are you so hostile towards Canderous?" that was restored through the Juhani Dialogue Restoration mod also returns where once it was missing due to the dlg file from this mod, suggesting that this may override something from that mod (even though there was no k_hjuh_dialog.dlg provided by that mod).
Adding on to the issue of flirty dialogue missing, in this particular conversation branch, with your mod installed and playing a male character, Juhani will say the line "Please, forgive me... I did not mean to insinuate that I... that we...", which is technically a "flirty" line she originally spoke only to female characters, but she doesn't say "Your...family?" as I previously mentioned, which is a line also reserved for female PC's.
When I removed the k_hjuh_dialog.dlg file from your mod, and the default conversation played with no errors, she doesn't say the "Please, forgive me" line, which means this mod does seem to be working somewhat to some degree at least.
I'm getting an error during one of Juhani's conversations, where she asks the player about his past. After she says the line "I am sorry if I am making you uncomfortable. I will fully understand if you choose not to answer." I get automatically kicked out of the conversation with an error message "Conversation node contains either an END NODE or CONTINUE NODE. Please contact a designer!"
Also, according to strategywiki, immediately before this line, she asks "Your job? Your childhood? Your life?" And as an intended flirty line for female players "Your...family?" However that last line doesn't play for me with this mod installed.