Custom Translator not working properly in some cases

Question

I was using custom translator, but the translation is different from that which is defined in dictionary in few cases.

[Details]

Subscription : S1

Region : US West

API Endpoint : https://api.cognitive.microsofttranslator.com/translate/?api- version=3.0&category=XXX&from=en&to=es&allowFallback=false

Training type : Dictionary-only Training

Trained dictionary type : Phrase Dictionary

Language pair : English - Spanish (Espanol)

Data in phrase dictionary

English	Spanish
Cat	Cat
Dog	Dog
Bat	Bat
Ball	Ball

Below mentioned are few scenarios where it isn't working.

1. request : "Cat" response : "Gato" (default translation response) ❌ expected response : "Cat"
2. request : "Dog" response : "Perro" (default translation response) ❌ expected response : "Dog"
3. same issue for "Bat" and "Ball"

BUT, when my request is a sentence instead of a word, it seems to be working fine ???

1. request : "I need a Cat." response : "Necesito un Cat." ✅ expected response : "Necesito un Cat."
2. request : "I need a Dog." response : "Necesito un Dog." ✅ expected response : "Necesito un Dog."

AND, I came across this unique scenario

1. request : "I have a Cat." response : "Tengo un gato." (default translation response) ❌ expected response : "Tengo un Cat."
2. request : "I have a Dog." esponse : "Tengo un Dog." ✅ expected response : "Tengo un Dog."
3. I got correct responses for "Bat" and "Ball" sentences. ✅

I have tried with other words as well, but didn't get expected translation response (when the request is just a word). I got correct responses when I used those words in a sentence as mentioned above.

Is it that single word translations are not supported ?

And for the word "Cat", Even when I used it in a sentence I got default translation in few cases as mentioned above.

Could you please help.

Thank You.