Yes, seems like that. I didn't made any changes in MCSDK host. My steps.
1. Made new dir like h264hpdec_h265enc
2. Used codecParams_dec.cfg, from H.264hp directory
3. And codecParams_enc.cfg from Hevc directory.
4. Changed demoSave2File.sh (I send you).
That's all. No scaler, as you said only H.264 dec (720)->H.265 enc (720)
It's really works, but the problem I reported above.
Best, Alexander Butuk.