UU Employers Compensation and Benefits Knowledge Base - Once an employee satisfies the Year of Eligibility Service, do they always receive the employer contribution?

Yes, employees who have satisfied the Plan's Year of Eligibility Service provision will continue to receive employer contributions from that time forward:

If the employee's hours are later reduced, they still receive employer contributions.
If the employee is terminated and rehired by the same employer, contributions restart immediately.
If the employee is hired by another participating employer, contributions begin upon hire. The new employer cannot require the employee to re-satisfy the eligibility service provision.

Remember that "eligible" means "must receive." Employees may not opt out of contributions due them.

We can also look to the Plan document (Section 3.4 & 3.5)

3.4 Period of Participation

An Employee who becomes a Participant shall continue as a Participant until the later to occur of the date of the Participant’s Severance from Employment or the date on which all the Participant’s Accounts have been distributed. For all purposes of the Plan: (i) a period of leave of absence shall not interrupt continuity of participation; (ii) a determination that a Participant has a Disability shall not interrupt continuity of participation; and (iii) the transfer of employment from an Employer to another Employer shall not interrupt continuity of participation. If a Participant incurs a Severance from Employment, he or she shall be ineligible to make or receive Plan contributions.

3.5 Reemployment

If a Participant incurs a Severance from Employment and is subsequently reemployed by an Employer, his or her Years of Eligibility Service shall be reinstated.