Should "Set Timeouts" return "invalid argument" for nonintegral values?

https://www.w3.org/TR/webdriver/#timeouts:

A timeouts configuration is a struct representing the timeouts for script evaluation, navigation, and element retrieval. It has a script timeout item which is an integer or null and is initially set to 30,000, a page load timeout item which is an integer or null and is initially set to 300,000, and an implicit wait timeout item which is an integer or null and is initially set to 0.

... but it seems "deserialize as timeouts configuration" will accept nonintegral numbers. Namely:

Set timeouts to the result of converting a JSON-derived JavaScript value to an Infra value with timeouts.

... will keep numbers as-is, and:

If value is neither null nor a number greater than or equal to 0 and less than or equal to the maximum safe integer return error with error code invalid argument.

The de facto behavior seems to be to return "invalid argument". See test_invalid_value[2.5-*: https://wpt.fyi/results/webdriver/tests/classic/set_timeouts/set.py?label=experimental&label=master&aligned

Start with the WebDriver Set Timeouts and “deserialize as timeouts configuration” sections cited in the issue, then compare their wording with test_invalid_value[2.5-* in webdriver/tests/classic/set_timeouts/set.py. Done means resolving whether nonintegral timeout values must return “invalid argument” and clarifying the specification accordingly.