CRA recognizes that failure to file a T1135 may not indicate carelessness or neglect

CRA considers that a s. 162(7) penalty for failure to file a T1135 form can be assessed beyond the normal reassessment period (or, under s. 152(4)(b.2), beyond the normal reassessment period plus three years where the taxpayer did not report income from specified foreign property in the relevant return) but, in such a case, CRA would have to “prove” that “although that error may have been made in good faith, it was an error that a prudent and conscientious person would not have made.”

Neal Armstrong. Summary of 26 May 2016 Alberta CPA Roundtable, 2016-0645001C6 under s. 152(4)(a)(i).