Got a peak this morning, 8 hours later got a blank circle on a new kit

I have been using clear blue advanced digital kits since a few months. 
I have a few holders, so when I get a peak I usually want to double check and I use a different holder and a peak comes up straight away. 
this month, I’ve gotten a peak on one of the holders and when I used another holder a few hours later, it showed a blank circle. 
is this concerning? Does this mean my LH surge was low?