[BP MB-39301] - Timer scan time keeps increasing on an idle cluster with a timer handler

./testrunner -i vikas-nodes.ini -t eventing.eventing_dataset.EventingDataset.test_eventing_processes_mutations_when_mutated_through_subdoc_api_and_set_expiry_through_sdk,nodes_init=4,services_init=kv-eventing-index-n1ql,dataset=default,groups=simple,reset_services=True,skip_cleanup=True,handler_code=n1ql_op_with_timers 

Exception: duplicated data in destination bucket which is not expected. Current : 3 Expected : 0  dcp_backlog : 0  TIMERS_IN_PAST : 0 lcb_exceptions : {'10.143.192.102': {}}

function OnUpdate(doc, meta) {

    var expiry = new Date();

    expiry.setSeconds(expiry.getSeconds() + 300);

    var context = {docID : meta.id, random_text : "e6cZZGHuh0R7Aumoe6cZZGHuh0R7Aumoe6cZZGHuh0R7Aumoe6cZZGHuh0R7Aumoe6cZZGHuh0R7Aumoe6cZZGHuh0R7Aumoe6cZZGHuh0R7Aumoe6cZZGHuh0R7Aumoe6cZZGHuh0R7Aumoe6cZZGHuh0R7Aumoe6cZZGHuh0R7Aumoe6cZZGHuh0R7Aumoe6cZZGHuh0R7Aumoe6cZZGHuh07Aumoe6cZZGHuh07Aumoe6cZZGHuh07Aumoe6"};

    createTimer(timerCallback,  expiry, meta.id, context);

}

function OnDelete(meta) {

    var expiry = new Date();

    expiry.setSeconds(expiry.getSeconds() + 300);

    var context = {docID : meta.id};

    createTimer(NDtimerCallback,  expiry, meta.id, context);

}

function NDtimerCallback(context) {

    var docID = context.docID;

    while (true) {

    try {

        var query = DELETE FROM dst_bucket where meta().id = $docID;

        break;

    } catch (e) {

        log(e);

        }

    }

}function timerCallback(context) {

    var docID = context.docID;

    while (true) {

    try {

        var query = INSERT INTO dst_bucket ( KEY, VALUE ) VALUES ( $docID ,'timerCallback');

        break;

    } catch (e) {

        log(e);

        }

    }

} 

"dcp_expiration": 3