In the US, most job-based health insurance plans include a stipulation which references the pre-existing condition exclusion period:
The time period during which a health plan won't pay for care relating to a pre-existing condition. Under a job-based plan, this cannot exceed 12 months for a regular enrollee or 18 months for a late-enrollee.
Am I correct in seeing a gap in coverage by interpreting the statement literally? If someone with a pre-existing condition were to become employed under such a plan, and the condition manifests such to render them disabled within a year of their employment, would they be legally not entitled to coverage by such a plan?
I have found some other references related to this but that link confuses me even more because it implies that insurance will not pay out at all if the claimant had a pre-existing condition from any time before the effective date that later renders them disabled.
Broadly, am I missing some other factor that would provide some relief to the claimant, like the expectation that previous insurance has paid out based on the diagnosis of a condition that would be considered pre-existing at a new insurer? Fortunately this is only an academic question, and I just don't know very much about how serious illness or injury is handled.
I am merely interested in broad strategies about how this would be handled in favor of the claimant, or if this is a known "defect" in the healthcare system.