msycamore said:

Scene order in English home video versions and 2004 Cut:

Drug evasion arrest --> Trial & "pain prods" (electro-shock batons) scene --> THX gets medical examinations --> THX is being monitored & researched --> LUH visits THX --> THX put in prison

Yes, I remember that. But first, a theory. My thinking was/is:

Lucas' original cut [1st version, 1970] was never seen when Warner Bros. took it away from him. WB then re-edited it (only removed some minutes of material -- by Lucas' own account) for theatrical release [2nd version, 1971]. Lucas' Star Wars success in 1977 gave him new clout to demand that THX 1138 be restored back to his original cut. So, it was this originally unreleased 1st version that was finally released in WB's 1978 theatrical "re-release" and, thereafter, on television.

Note: If your preservation of the locally(?) re-edited Italian TV (with flashback edits, voice-over, and "rush-job" snipping) has the missing SEN-talking-to-children shots, then it was recorded before (or shortly after) 1983. Otherwise, it was a "next version" recording.

The next version (so goes my theory) was with the home-video releases. Lucas himself removed some of the SEN-talking-to-children shots and re-ordered the THX-caught sequence. This was Lucas' second cut [3rd version, 1983].

The next version was the new home-video releases (notably DVD), which contained old outtakes and extensive CG & digital manipulation. This was Lucas' third cut [4th version, 2004].

(I haven't reviewed the 2010 Blu-ray release to determine if it is yet another cut or just color-timing cleanup.)

This makes sense, I believe, because it fits with Lucas' incessant tinkering with his already released works. (Or ... maybe it's just his father's business sense, in him, to resell the same product ... for more enjoyment and greater efficiency ... to make another buck?)

Anyway, I reviewed the 1997 Bravo letterbox broadcast recording (the US laserdisc vintage, I expect) and came up with your same "English home video versions and 2004 Cut" sequence of THX-caught:

[dissolve] 2 roboPolice escort THX up hallway [fadeout]
readout: "Drug Evasion Arrest" "Place In Research Cell Pending Trial"
beating by roboPolice w human supervisor
readout: number counting 5 to 6
trial & computed verdict w readout: "Conditioned" "Detention"
[dissolve] electro-prod live-practice by roboPolice in white limbo [fadeout]

technicians neuro-conditioning THX
THX & LUH join in white limbo & separation by roboPolice w human supervisor [fadeout]
[fadein] delivery to detention in white limbo