mousiopeprobably your mouse tracking speed bugging out, try a different dpi, disable angle snapping or try a different mousepad or updating mouse firmware
but im guessing you need a new mouse
This is definitely your issue, you may not need a new mouse, though you might prefer that over the other options for a fix.
Mousepads matter quite a lot in Max Tracking speeds here's an example that I left in a review for the Ripper XXL series mousepad.
Mice Tested:
G400s
G400
WMO 1.1a
Zowie FK
Logitech M-UAE96
Mousepads Tested:
XTRAC Ripper XXL
XTRAC Hammer
Steel Series QCK+
Custom Cloth Mousepad (of the generic cloth type)
With the G400s @400 DPI 1000Hz
Ripper XXL 3.2 m/s
QCK+ 4.6 m/s
Hammer 4.2 m/s
Custom 4.0 m/s
G400 @400DPI 1000Hz
Ripper XXL 2.8 m/s
QCK+ 4.2 m/s
Hammer 3.7 m/s
Custom 3.6 m/s
WMO 1.1a @400 DPI 125Hz
Ripper XXL 0.9 m/s
QCK+ 1.6 m/s
Hammer 1.3 m/s
Custom 1.2 m/s
Zowie FK @450 DPI 1000Hz
Ripper XXL 3.0 m/s
QCK+ 4.4 m/s
Hammer 3.9 m/s
Custom 3.7 m/s
Logitech M-UAE96 @400 DPI 125Hz
Ripper XXL 0.8 m/s
QCK+ 1.4 m/s
Hammer 1.0 m/s
Custom 1.0 m/s
I don't know exactly how to describe this but in my experience Solid Black Mousepads > everything else and typically mousepads that have a bit more resistance tend to have the best max tracking speed for a mouse, while mousepads that seem to have more glide to them are significantly worse.
Side note: Common side affects of hitting your max tracking speed. Looking straight up/down almost instantly, crosshair just suddenly skips like 10 degrees of movement either left/right, massive negative acceleration.
FYI new gaming mice rarely have this issue as all the new logitech mice with the G502 sensor can do like 7+ m/s on basically any cloth surface, Zowie is around 5-6m/s with their latest series of sensor, razer DA chroma series or anything recent is also 5+m/s on basically any cloth surface, etc.
-edit-
@OP Most mice do best around 400/800 DPI so you don't really need to change that, if you're not using 1000Hz for your mouse though you should definitely try that. Otherwise your options are use a different mousepad (I really like the Steel Series QCK pads, from what I've been told Puretrak Talent mousepad has a similar max tracking speed if you prefer that) OR you could get a new mouse.