Words incorrectly included with numbers in placeables

I am seeing words being incorrectly recognized as part of placeables in source text segments.

For example:

572 a 1474 mg/dl (Portuguese) is being translated as 572 a 10.6 mg/dl in the target when I do not use "Quick Place".
The correct translation is "572 - 1474 mg/dL"

The placeables underlined in blue in the source segment are "572 a" and "1474 mg/dl". "572 a" is incorrect, because "a" should be translated as "to" or "-" in this case. Also, I do not want "mg/dl" selected as a placeable, because I am changing it to "mg/dL" in the target.

How can I get Studio to select ONLY the numbers?

Thank you for your help!