It is not shown on the list yet, but the file is there:
https://mirrorbits.lineageos.org/full/oneplus3/20190302/lineage-16.0-20190302-nightly-oneplus3-signed.zip
twrp-3.2.3-0-oneplus3.img has finally solved the decryption problem many of us had for all Firmware/Modem after OB31 :good:
I just updated TWRP, then "Stable5.0.4 Firmware+Modem_OnePlus3.zip" (from OB31), and everything seems fine now.
Thanks for this information. I had the issue with the OB32 firmware and now I know that I will not install the OB33 firmware because this ugly decryption bug is not solved... :(
It took some time until I found out the exact procedure to sideload the old OB31 firmware... You still need TWRP, but...