What to do if Salesforce Trigger is not working as expected?

I have a trigger on release(Child of Opportunity) record. The logic for the trigger is in the handler class. I am updating checkbox to true on Opportunity(Parent) whenever release record edited or inserted. The default value for checkbox needs be false and if any record inserted/updated on release object has Release__c.Test__c value starts with other than ‘14%’ then checkbox needs to set to False.  I mean to say checkbox will be set to true only when all record has Test__c = ‘14%’ else set to false. I tested my trigger logic but it is not working as expected also with my logic some time I get Maximum CPU error. Any help or suggestion?

trigger updateCheckbocOpp on Release__c (after insert, after update) {
    list<Release__c> bqList = new list<Release__c>();
    for (Release__c childObj : Trigger.new){
        listIds.add(childObj.Opportunity__c);
    }

    oppsToUpdate = new Map<Id, Opportunity>([SELECT id, Set_Rel__c,(SELECT ID,Test__c FROM Plan_Sum__r) FROM Opportunity WHERE ID IN :listIds]);
    system.debug('testing trigger >> ' + oppsToUpdate);
    for (Opportunity opp: oppsToUpdate.values()){
        for(Release__c bq :opp.Plan_Sum__r){
            system.debug('Release Record >> '+bq);
            opp.Set_Rel__c = true;
            if(!bq.Test__c.startsWith('14%')){
                opp.Set_Rel__c = false;
            }
        }
    }
    system.debug('Update >>>' + oppsToUpdate.values());
    update oppsToUpdate.values();
}