Try mining just eth and not dual mining. If it works at least you can mine the profitable one.
In case that wasn't already the case (I believe it was), I tried specifying -mode 1 and got
ETH: 1 pool is specified
Main Ethereum pool is eth-eu1.nanopool.org:9999
Cannot load OpenCL library, AMD cards will be unavailable
Be careful with overclocking, use default clocks for first tests
Press "s" for current statistics, "0".."9" to turn on/off cards, "r" to reload pools, "e" or "d" to select current pool, "x" to select GPU
CUDA initializing...
NVIDIA Cards available: 2
CUDA Driver Version/Runtime Version: 11.1/8.0
GPU #0: GeForce RTX 2080 Ti, 11018 MB available, 68 compute units, capability: 7.5 (pci bus 1:0:0)
GPU #1: GeForce RTX 3080, 10018 MB available, 68 compute units, capability: 8.6 (pci bus 3:0:0)
Total cards: 2
You can use "+" and "-" keys to achieve best ETH speed, see "FINE TUNING" section in Readme for details.
ETH: Stratum - connecting to 'eth-eu1.nanopool.org' <151.80.59.84> port 9999 (unsecure)
ETH: Stratum - Connected (eth-eu1.nanopool.org:9999) (unsecure)
ETHEREUM-ONLY MINING MODE ENABLED (-mode 1)
ETH: eth-proxy stratum mode
Watchdog enabled
Remote management (READ-ONLY MODE) is enabled on port 3333
ETH: Authorized
Setting DAG epoch #366(3.86GB)...
ETH: 10/04/20-13:09:32 - New job from eth-eu1.nanopool.org:9999
ETH - Total Speed: 0.000 Mh/s, Total Shares: 0, Rejected: 0, Time: 00:00
ETH: GPU0 0.000 Mh/s, GPU1 0.000 Mh/s
Setting DAG epoch #366 for GPU0
Setting DAG epoch #366 for GPU1
Create GPU buffer for GPU0
Create GPU buffer for GPU1
GPU 1, GpuMiner cu_kd failed 8 (0), invalid device function
GPU 0, GpuMiner cu_kd failed 8 (0), invalid device function
GPU 0, Calc DAG failed!
GPU 1, Calc DAG failed!
ETH: 10/04/20-13:09:34 - New job from eth-eu1.nanopool.org:9999
ETH - Total Speed: 0.000 Mh/s, Total Shares: 0, Rejected: 0, Time: 00:00
ETH: GPU0 0.000 Mh/s, GPU1 0.000 Mh/s
ETH: 10/04/20-13:09:37 - New job from eth-eu1.nanopool.org:9999
ETH - Total Speed: 0.000 Mh/s, Total Shares: 0, Rejected: 0, Time: 00:00
ETH: GPU0 0.000 Mh/s, GPU1 0.000 Mh/s
GPU 0 failed
Setting DAG epoch #366 for GPU0
GPU 1 failed
Setting DAG epoch #366 for GPU1
GPU 1, GpuMiner cu_kd failed 8 (0), invalid device function
GPU 1, Calc DAG failed!
GPU 0, GpuMiner cu_kd failed 8 (0), invalid device function
GPU 0, Calc DAG failed!
ETH: 10/04/20-13:09:40 - New job from eth-eu1.nanopool.org:9999
ETH - Total Speed: 0.000 Mh/s, Total Shares: 0, Rejected: 0, Time: 00:00
ETH: GPU0 0.000 Mh/s, GPU1 0.000 Mh/s
GPU 1 failed
GPU 0 failed
ETH: 10/04/20-13:09:43 - New job from eth-eu1.nanopool.org:9999
ETH - Total Speed: 0.000 Mh/s, Total Shares: 0, Rejected: 0, Time: 00:00
ETH: GPU0 0.000 Mh/s, GPU1 0.000 Mh/s
ETH: 10/04/20-13:09:46 - New job from eth-eu1.nanopool.org:9999
ETH - Total Speed: 0.000 Mh/s, Total Shares: 0, Rejected: 0, Time: 00:00
ETH: GPU0 0.000 Mh/s, GPU1 0.000 Mh/s
ETH: 10/04/20-13:09:49 - New job from eth-eu1.nanopool.org:9999
ETH - Total Speed: 0.000 Mh/s, Total Shares: 0, Rejected: 0, Time: 00:00
ETH: GPU0 0.000 Mh/s, GPU1 0.000 Mh/s
ETH: 10/04/20-13:09:52 - New job from eth-eu1.nanopool.org:9999
ETH - Total Speed: 0.000 Mh/s, Total Shares: 0, Rejected: 0, Time: 00:00
ETH: GPU0 0.000 Mh/s, GPU1 0.000 Mh/s
GPU0 t=60C fan=41% P=53W, GPU1 t=43C fan=0% P=104W
Total GPUs power consumption: 157 Watts
WATCHDOG: GPU error, you need to restart miner