Why I get another spectrum when upconvert an o-qpsk baseband signal with a bladerf compared to a hackrf device?
One source of this is spectral regrowth (overdriving a device into saturation such that the pulse shaping that limits the spectrum is degraded), but compared to typical spectral regrowth spectrums I have seen, this looks more like your signal was greatly attenuated and then amplified together with noise, and then that combined signal passed through a bandpass filter. Check if there is a 5 MHz filter earlier in the Tx chain to further support this theory, and then also try to reduce the power level at the input to the device.