Using MCP4921 DAC for wave generation... strange line on scope reading.

Hi all. Hope you are all well. :0
I wonder if anyone could help me.
I have an MCP4922 DAC set up outputting a sine wave (values 0-4095). The wave shows nicely except for one thing… A glitch on part of the waveform which shows up as a line and when zoomed in, a small pulse blip.
Ive included images as attachments.
would anyone know what these are?
The wavetable I am using works fine using a PWM dac…


IMAG012.BMP (47 KB)

IMAG013.BMP (47 KB)

looks like that the output is disturbed by an interrupt.
Unfortunately you didn't post any code or library you are using.
So if the library isn´t using any interrupt, you could try the noInterrupts() argument. Otherwise you have to disable any other interrupt, that you don't use by hand. (especially PWM, tone()...)
I'm interested in your project:
My attempts getting out wavetables from the 4922 (even with only 256 steps) were unsatisfactory: I was only able to get out about 1kHZ, so if you could post your code (and perhaps the used library) I'll try to help you!