"Con chim sẻ chia sẻ bánh mì."
Translation:The sparrow shares the bread.
Yes, the hỏi tone here sounds unclear. I think the vowel e has affected the quality of the tone. In Vietnamese standard voice, the e sound is /ɛ/ while this speaker pronounces e nearly like /eə/. This vowel deviation makes the word last longer and the hỏi tone is protracted. That is why it sounds a lot like the huyền tone.
Generally, tones are pronounced almost consistently. Of course, there are some small deviations but they're rare.