I've encountered some FTIR weirdness in my day too, so I can understand the urge for a quick answer. But this is a learning forum, so we'll start with hints.
Because other atoms cause shifts, 704 cm-1 isn't what you should look for. And the intensity of the peak is , while unnaturally high, can be based on sample size and the like. Instead, you should say that you have found a strong, sharp peak in the 700 cm-1 area.
You can find many tables that identify bands and peak types for FTIR. Here's one from Wikipedia:https://en.wikipedia.org/wiki/Infrared_spectroscopy_correlation_table Do you see something associated with a strong, sharp peak in the vicinity of your peak? And can you exclude a possible contamination of your sample by that functional group for some reason?