A shitty local bank back home truncated without telling you as well. Didn't realize it until they rolled out a mobile app and my password didn't work. After complaining about it, a friend who worked at said bank as a teller said to try truncating to 8 chars and it worked. :rage:
Apparently it was known internally, as they used some ancient system behind the scenes that would only support a max of 8 chars, and the website just truncated your password and passed that on. The new app didn't truncate and would get an error response.