Lime Tx spectrum in CW Tune


Hi all.
When I am activating my Lime SDR into Tx om Tx channel 1 using CW and "tune" and look at the modulation spectrum (using a HP 8561E SPA) I do not get one single tone but a whole spectrum looking like it is excited by a square wave rather than a single CW sine tone. When listening on a radio I get the same response. Changing the drive level does not change the spectrum shape, just the level. Frequency is 432.174 MHz and I read +10 dBm output on the highest peak tone in the spectrum when at maximum drive setting.
Exciting the Lime via SDR-console using a FT8 signal from MSHV via Line1 and in USB exhibits the same wide spectrum.
Has anyone else seen this? Have i missed some setting of the SDR-console Tx controle settings? Any other idea on what this might be caused by?
I am on FW version 4 in my Lime according to what SDR-console reads.
73 / Ingolf, SM6FHZ

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