ESPhome and flow rate meter high number of pulses

I have built a small watering system for my vegatable plot part of which includes a flow rate meter connected to a NodeMCU to notify me if the flow rate is above what would normally be expected when watering is taking place which might signify a leak in the system.

It has been working well for several weeks but today it has notified me several times because it has recorded over 130000 pulses a minute, this is with no water flowing through the system and no leaks.

To try and point me in the right direction, is this likely to be a result of a fault with the hall effect flow sensor or with the nodeMCU itself.

Thanks for any help.