ETFs are structured to minimize capital gains distributions via "in-kind" transactions involving an Authorized Participant. These are not considered sales.
Fund managers of mutual funds and individual investors are not entitled to such protection from taxation.
Superficial losses are defined by section 54 of the Canadian Income Tax Act (ITA). If a capital loss is realized in such a way that it falls under the definition in the ITA, the loss cannot be used in the year realized but, rather, it will be added to the adjusted cost base of the property to reduce future gains or increase future losses.
In other words, ...
You haven't said the value of the cheque, which obviously matters a lot. Nor have you stated the bank you use.
Generally a bank will be able to cash foreign cheques, but it's probably more complicated because of the foreign currencies.
When I had a similar situation, I opened a US$ account and was able to deposit the cheque there.
Certain banks advertise ...