I'd still very much count that as casting and teleporting mid battle. Hell mathy literally comments that this is now an actual battle and not a slaughter.
if several different groups of enemy charging her isn't combat then I don't know what is at this point.
Well let's take a look at that shall we?
each teleportation starts to be met with shouted warnings as the most strong-willed push through the aura of confusion to meet Branulhune with their own blades. You and your shadow still reap a bloody harvest but it is now a battle, rather than a slaughter.
Hmmm, why that almost seems to be referring to when Mathilde is in melee and killing people with her sword, comparing the current "They can actually respond to Mathilde teleporting next to them and swinging" to the previous "Mathilde teleports in and murders them before they can effectively respond due to surprise, her shadow, and her aura of dread, and in one case being distracted with a spectral bear."
Mathilde doesn't like that, and so we next get the next bit that is very obviously her casting a debuff spell where she's about to teleport and engage instead of just casting shadow knives, in order to make things easier and less risky.
You don't like fair fights so you switch from Shadow Knives to Melkoth's Mystifying Miasma for weaving your teleportation cantrips into, making sure that wherever you appear there is also a field of jittering time, sending even the most skilled warriors off-balance as their well-trained reactions encounter the concept of time as a variable. Blades lifting to parry a swing moving a hair too fast or too slow, feet stumbling as one moves slightly faster than the other, sights and sounds taking a fraction longer to arrive and shaving just enough time from their responses to make all the difference.
Then, if we go back and look at the actual uses of teleportation before that, and we can find a very notable trend, of her teleporting
after she's removed all nearby threats with her sword.
Then you interweave Smoke and Mirrors into a casting of Shadow Knives aimed at the nearest Kul, and you disappear from where you stand with a swirl of fog.
before they begin to scatter. With another burst of knives into the back of the nearest, you're gone.
you're there to slice first through the haft, then through their wrists. Then you disappear again, this time with the teleportation cantrip woven into a recast of Dread Aspect.
From this we can pretty easily draw the conclusion that while Mathilde is indeed teleporting in the middle of a battle, she is doing so
when not threatened in melee, and is using the teleportation to engage people, rather than to disengage.
This also makes sense, as this means she can take her time with her spells and not worry about being interrupted or rushing, and thus have less worry about being stabbed while distracted, or worse, a miscast.
This would thus, you know, support what I originally said, and that you originally quoted, that Mathilde is teleporting
into fights/melee, not out of them, let alone
casting battlemagic in melee like you tried to argue earlier. Hell, nothing even implies anyone is getting close enough to charge Mathilde when she teleports.
Now, I am aware that you'd like to come out of this looking intelligent, so I will acknowledge that you are technically correct that Mathilde was casting during an ongoing battle, but you have been very obviously incorrect in every single other statement you'd made in this discussion so far, and you have quite literally quoted the bits of the update that showed you as such.