It is well known here that Reolink and BI do not play well together.
Lots of threads here documenting how poor a reolink/BI combo is.
Here is a
post that kinda summarizes the issues with BI:
"I can concur that I'm having the exact same issue.
However, with the number of ongoing issues I've had to deal with over the last 6 months, Reolinks just ain't worth it anymore. I've also dealt with the BI developers and Reolink's Support which is how I got the firmware, which, after 6 months, haven't been released to the public as yet.... 
Just the past weekend we were robbed and the Reolinks were nothing more than an absolute waste of space, time and energy on a wall.
BlueIris SHOULD remove all references to Reolink and clearly state that the brand is not supported. Full stop.
As such, I'll echo @sebastiantombs , @SouthernYankee and numerous others whom held the same view when I first joined this form in search of some enlightenment on all-things-not-working-re-Reolink and all-possible-workarounds-to-hopefully-make-it-work-re-Reolink. It's not worth it. It's a difficult pill to swallow, but you've burned cash and Reolink will just pay you until you cannot return the crap for a refund."
We even have a
master thread documenting these issues, along with the poor night time performance.
Please post your Cameras Status page from BI that shows your KEY, similar to this screenshot of a member here where they had set these cameras to 15FPS within the cameras (I suspect you will be missing motion that you do not know you are missing....):
Now look at they key - that is the iframes ratio.
Blue Iris works best when the FPS and the iframes match. Now this is a ratio, so it should be a 1.00 if it matches the FPS. The iframes not matching (that you cannot fix or change with a reolink) is why they miss motion in
Blue Iris and why people have problems. This is mainly why people are having issues with these cameras and there are many threads showing the issues people have with this manufacturer and
Blue Iris. It is these same games that make the camera look great as a still image or video but turn to crap once motion is introduced.
The
Blue Iris developer has indicated that for best reliability, sub stream frame rate should be equal to the main stream frame rate and these cameras cannot do that and there is nothing you can do about that with these cameras... The iframe rates (something these cameras do not allow you to set) should equal the FPS, but at worse case be no more than double. This example shows the cameras going down to a keyrate of 0.25 means that the iframe rates are over 4 times the FPS and that is why motion detection is a disaster with these cameras and
Blue Iris...A value of 0.5 or less is considered insufficient to trust for motion triggers reliably...try to do DeepStack with those lower ratios and it will be useless in many situations...
Compounding the matter even worse...motion detection is based on the substream and look at the substream FPS - they dropped down to below 6 FPS with an iframe/key rate of 0.25 - you will miss motion most of the time with that issue...DeepStack probably won't work at all for certain fields of view...
Look back of videos people have posted here where Reolink/BI combo completely missed a motion event. There is one here somewhere that completely missed a guy pulling his car into the garage.
If all you have are reo's, then I highly suspect there are events that you are missing.
Or it could be some weird setting you made, but without screenshots of a camera and all the tabs showing motion, recording, etc. it is a guess.