My Keyword Density Checker is acting possessed, spitting out zero frequency for critical content optimization terms!

i've been polishing up our 'Keyword Density & Frequency Checker' tool lately, and honestly, it's been acting a bit... off. Like, seriously off, and it's driving me nuts.

The tool is supposed to accurately count keyword frequency and density from user-provided text. But for the last few days, especially with some critical content optimization terms, it's reporting a flat zero frequency and density, even though the keywords are clearly visible in the input. it's making our internal QA a nightmare.

Here's an example of the weirdness:

// Input Text Sample:
"Our content optimization strategy relies heavily on smart keyword usage. This keyword usage is key for good SEO."

// Expected Output for 'keyword usage':
Frequency: 2, Density: X% (based on total words)

// Actual Tool Output:
Processing input...
Keyword: 'keyword usage' -> Frequency: 0, Density: 0%
ERROR: TextParseFailure - Input string returned empty match set for query.

Has anyone else run into similar phantom zero issues with their text parsing or regex in web tools? i've checked the regex, tried different input encodings, but nothing seems to stick. any thoughts on what might be causing this weirdness? help a brother out please...