The situation depicted above is a seki no matter the ruleset. If Black plays first, he gets captured and White will have enough space to create two eyes. If white plays first, she gets captured immediately. Thus, neither player can sucessfully attack the other and they have to agree to “truce”.
It is not a “bent 4” shape by any means. Unfortunately Bent 4 is a complicated position which is often misquoted, but in the above position there is no chance for either player to start a ko or anything. Whoever plays first loses the corner, no tricky business.
As to why the software does not mark it as a seki, the answer is simple. The software is wrong. Note that the picture taken is “Leela” and NOT “Leela Zero” (which is the modern superhuman bot). The original “Leela” (at least its “latest” - though still extremely old - version) is pretty “bad” (in the sense that it does not even approach dan levels) on 9x9. It is not to be relied upon for any complicated scoring.
If you would like to explore any of the positions deeper, let us know I (or someone else) will be happy to create a demo board displaying some of the more crucial variations.
the current state of the group is seki; a.) black moves first and white can make a living shape by making two eyes after he captured the black stones, or b.) if white moves first he puts himself into atari which leads to losing the group
ergo: its a seki, both players normally wont play there (unless a ko appears somewhere else on the board)