When flow collection is turned on, there is an annoying delay before collection actually happens, especially with IPFIX, counting in minutes. There are at least two reasons for that:

1. in the CNO / ovn-k layer, flow exports are enabled via a config change that triggers a rewrite of the DaemonSet declaration, which in turns makes kube restarting the pods ; ultimately at pods startup, the OVS command to enable ipfix exports is executed. The wait for pods restart takes some time.

2. ipfix protocol relies on the exporter sending template definitions to the collector at regular intervals (configured to 10min in OvS afaik). The collector can't do anything with the received data before it receives the definition templates. It's not clear to me at the moment if the templates are sent right after the export is enabled (it doesn't seem so). It makes it important also that the collector is ready before the exports are turned on.