WordPress has a particular mode that stops interactions while it updates. This is called servicing mode and will usually last just some seconds. https://www.evernote.com/shard/s667/sh/76def5fb-a10f-fc71-dca2-e8e4c03f57c0/ALm6OPKz0hXaqsna9liFE-ftQC_erijpkpWXO_R0s7EgyTLP-wARq54GjQ