In the test SubscriptionBasic/023.js, an attempt is made to check the compliance with the PublishingInterval of 2000ms using DataChanges reception after 3 Writes.

Sometimes this test fails with this kind of error:
"Expected a PublishingInterval of 2000 but actual interval was 2441.3333333333335;Expected a value less than 7300 and greater than 5700 but received 7324. "

After some investigation, it seems that the server is not able to send the PublishResponse in time because it receives the PublishRequest late and even by answering immediately cannot comply with the PublishingInterval because he has no Publish token available to do so.
I attached a TCP dump capture that shows that the server responds immediately whereas PublishRequest are sent every 2 seconds by UACTT, in this particular case the tests succeeded but even there we can observe the server is limited by the client PublishingRequest sending frequency which is not the purpose of this test script.

I suggest the client sends more PublishRequest tokens, or increase their frequency or at least provide a new PublishRequet as soon as it received a PublishResponse