Not since they lost their air defence system...
“Not since they lost their air defence system...”
If you stick it out through the stuttering and bad English of the source you linked, you might note that he says that the IRIS-T system that he claims was hit, is a short range Air Defense system, and the the Su-34s that were shot down, were far outside the range of that system.
Send more of Russia’s scarce front line fighter-bombers and pilots - they are delicious!