I was doing another experiment and checking if the blueprint containing the splitter was rotatable,
I noticed the problem occurred when rotating.
At that time, I still did not know that it would not split if placed in front.
I think that there is no problem that it will not be split when putting it ...

Sorry.
I posted images of other tests.
I recreated it.

https://wiki.factorio.com/Inserters
It says
"If a belt is in the same orientation as the inserter, the item will be placed on the right-hand lane, from the belt's perspective."

Is the splitter not the same design as the belt?

I read them.

Spliter not spliting when close to inserter
https://forums.factorio.com/viewtopic.php?f=23&t=27051

[0.12.31] Splitter/inserter interaction issue still present.
https://forums.factorio.com/viewtopic.php?f=7&t=24617

There are differences between putting on a belt and putting on a ...

splitter is not rotationally symmetrical.

There are differences between putting on a belt and putting on a splitter.
In the case of a belt it is rotationally symmetrical,
In the case of a splitter it is not.
Is this a bug?

I remember that the belt placement process changed in the past, but have ...

I like your concept.
I added some conditions.
A. 11 tiles Height. (MAX pipe-to-ground length)
B. Merging the connector-block to the transfer-block. (no connector-block)
C. Not changing base-transfer-block parts. (only adding parts. simplified removing)
D. Including big-electric-pole.

base ...