The majority of parish councils are small, very small rural councils with the minimum of 5 parish councillors. They hold the minimum number of council meetings, 1 every 3 months or so. There is potentially a high risk of accidental councillor disqualification, especially over the summer.
As an example, the council must have its Annual Parish Council meeting in May but as August is holiday month many schedule their next council meeting for September. This means that the next meeting is December to approve the precept and so on.
Many older parish councillors have no need to take their holidays during school holidays so they go away in September. In this example the councillor will be automatically disqualified in November and there is nothing that can be done unless an extraordinary meeting is called by the Chairman.
Continuing to act as a councillor when disqualified may have severe consequences.