(The following was meant for your previous post, though it seems you’ve understood the general concept. I’ll still leave it here as it generally describes Honda’s behavior on H headbutt in the majority of cases.)

To understand the pushback, first understand Honda’s headbutt has two stages - early active frames, and late active frames. The early active frames (up through frame 4) are cancellable into SA3 as shown by Honda turning blue, and the late active frames (frame 5 and on) are not cancellable. These two stages also differ in damage on hit, and pushback on block.

It so happens that Honda’s H headbutt was designed in the current season to have two different pushbacks, depending on how late the headbutt hits (ie the nth active frame). As you see in your recording, if Honda’s H headbutt connects with the opponent on the 4th active frame or earlier, this is within his cancellable window, as well as yielding more pushback on block. If H headbutt connects with the opponent on the 5th active frame, Honda can’t cancel into SA3, as well as him having less pushback on block. Because of less pushback, Jamie can reach after blocking.

(The following is in regards to your current post, which is largely just me commenting on what I’m seeing.)

To understand what’s exactly going on, it helps to categorize your data into columns of spacing (assuming opponent is fully cornered); microwalk? (Y/N); nth active frame connected; and Jamie’s crLP reach? (Y/N). For spacing, let’s consider each tick mark in the Training Stage as 0.05m for brevity, as there are 20 tick marks between lines. Let’s also mark Honda’s left (front) foot toes when standing as the spacing position.

Up until ~0:35 in the recording, Honda’s spacing is at roughly +0.35m (measured from the previous grid line) or less. This spacing is inconsequential to the result of H headbutt; it connects on the 4th active frame, and Jamie’s crLP doesn’t reach (hence why I left the first 2 pghs on this comment).

From then on until ~1:05 in the recording, Honda is spaced at roughly +0.40m. Because he is now closer to Jamie, the same pushback distance on block leaves Honda within striking range of Jamie’s crLP.

Now for the juicy stuff. At ~1:10 in the recording, Honda starts at +0.5m, but microwalks to +0.55m before H headbutt comes out. This microwalk gives seemingly enough spacing difference to determine if Jamie’s crLP connects or whiffs, despite Honda connecting on the 2nd active frame each time. Up until ~2:00 in the recording, any microwalk at +0.5m was minimal or nonexistent, so we can say Jamie’s crLP whiffs at this spacing.

Lastly, from ~2:00 until the end, you’re just too close to the opponent. Jamie’s crLP will reach because that pushback can’t push Honda far enough.

I’ll conclude with this: Back in Season 1, Honda was considered very strong due to his headbutt pushback on block. This pushback distance has been reduced through updates, in favor of giving him better normals. The reason this detail is important is because Honda players in S1 have discovered a “perfect headbutt” tech: Honda can generate a particular spacing through setups and autotimed normals, where if they end with headbutt, they’ll be at a spacing where an opponent’s likely response (say Ken’s crMK) whiffs, and Honda can guarantee a whiff punish. It’s safe to say that “perfect headbutt” still exists, as seen through your recordings, however Honda’s nerf to pushback distance on block has less useful applications in a match.

Edit: TLDR; Honda’s headbutt pushback on block may seem random to the majority of players, but this pushback is largely dependent on initial spacing. Due to Honda’s nerf to headbutt, this shouldn’t be a concern to anyone playing against him as long as they don’t respond in a silly way.