This appears to just be a visual bug - I was curious and checked just now and I was able to craft it even though it's not showing up as unlocked on the pattern/catalyst screen.
I'm not 100% sure, but I think this happened because I already had a red border Taipan-4fr when I started the quest to get the free patterns at the Enclave/relic, and I somehow skipped a quest step.
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Same with mine, but I was able to craft the weapon. I received another deepsight taipan and it does not show that I can extract the pattern from it.