cvt dropping rpms while in manual mode

was merging on the highway and was around 3000 rpms and was in 4th, let off the gas a little then rpms went down to 1000 almost instantly, even when i tried to downshift it didn’t do anything. tried giving it gas then it spiked back to where it was but still wanted to drop after letting off throttle

is this a transmission issue or just normal cvt behavior