Basically, the error_fields method is returning a 1 instead of an array. I've seen this with some other functions such as 'errors'. When running the same code with Template Toolkit or Template Alloy, the code works as expected.
Sorry late reply.
Value after IN must be arrayref. I suppose you specify list(not array) and last element is used. Please save into variable as arrayref and reference it.
I've detailed the bug here:
https://stackoverflow.com/questions/38193910/textxslate-returning-incorrect-value-for-function-call
Basically, the error_fields method is returning a 1 instead of an array. I've seen this with some other functions such as 'errors'. When running the same code with Template Toolkit or Template Alloy, the code works as expected.