You did miss something. Test range dummies are set to always take 2.13x headshot damage from all guns.
Here's the rough order of things:
CTE - DICE set 2.13x headshot multi on all guns that were on 2.0x
CTE - I'm super happy, immediately went to test range a "confirmed" that all guns had the new multi...including SR338 which now had a 49m OHK range. I thought "ah, so that's how they are planning to make SR338 useful! Excellent. DICE are truly balancing everything through direct and indirect means".
CTE - DICE mysteriously lowered DMR headshot multi back to 2.0x. This confused everyone because DMRs had nothing to lose/gain between the different headshot multis (45 * 2.13 = 95.85), and doing that extra 5 damage with headshots would've been nice.
CTE - Tiggr's only response on the topic was 5 words - "to bring in that range" - which didn't really make sense because DMR TTK was unaffected in any case. But I didn't think too much about it, didn't really affect DMRs and SR338 was definitely counted as a sniper rifle (or so I thought). I confirmed SR338 still had a 49m OHK on test range.
Retail - spring patch launches. Within just a few minutes of using SR338 I immediately realize it's OHK range is nowhere near 49, in fact it feels far shorter than that. Then I found out about the test range bug.
Retail - then it hit me. DICE counts SR338 as a DMR. The headshot multi nerf on DMRs suddenly all made sense - it was done SOLELY to nerf SR338. In CTE DICE had made no attempts to note down that SR338 was also actually affected. Tiggr's "to bring in that range" comment was more of a white lie than anything.
This is why I'm angry and feel DICE is biased against semi-auto marksman guns.