CM, did you acquire these shares (ZENE: CDN) directly from the company in 2014:

"The shares in the TFSA came from Zenith in the form of a direct purchase where I beleive I paid $1:00US, also way back in 2014."

I am of the belief that Zenith shares only traded on the OTC market much later than 2014 under the symbol "ZHCLF" post-SPINCO.

KBC and RVXOT may have better information on this subject.

Shares purchased in US funds can be held in US funds in your account or you can choose to convert to CAN funds. At least this has been my experience. 

Koo