IIRC with some test runs with MCCI LMIC v3.3/4.0 on TTN V3 (LoRaWAN v1. 0.3) i did notice more than once, on (rough) average about 10 (or some less) downlinks per 100 uplinks.
These are MAC commands sent by the network server to optimize network operation and should not count as part of the downlink FUP (because not controlled by the user).
I haven’t done any further investigation, assuming this is just part of / normal for V3.
The number of uplinks and downlinks can be easily visualized by using the LMIC-node example application.