Unable to write unicode in the fillable input fields in Adobe Sign

I have created a template in Adobe Sign with few input fields such as a text field, a number field etc. If the signer or pre-filler input english letters it shows the text to the next signer and on the final signed pdf correctly. But if the input text is non-english (I tried Bengali letters), the input text does not show up to the signers or the final pdf. In fact, if the text is mixed, only the english letters can be seen. Am I missing something or non-english characters are not supported on Adobe Sign? Thank you.