Change log for beta 0.81:

ai: water navigation
ai: objects in water are no longer estimated as good cover
ai: squad leaders far enough from fighting to hear it but not see it continue with their objective, rather than stay idle momentarily
ai: commander attempts to keep the comms truck block defended at all times
ai: crates are now avoided while driving, if speed is too low
ai: commander choosing random positions in blocks for sending troops attempts to avoid water now
options: commander messaging slider was working vice versa, oops
config: previous antialias setting was not read from config.xml
map2: radar truck added, slight changes overall to adjust for it
map5: south area of the map redesigned, several optimizations
optimization: large platforms and walls ended up extending static geometry regions, weakening rendering culling
inactive-regions: vehicle and navigation bug fixes
weapons: burst mode weapon class supported, class="4" and burst_shots="x", otherwise specifications work similar to 0-class weapons
weapons: shotgun/sniper-class weapons now require walking when pumping/bolting
online: soldier placement stuttering when seated in vehicle fixed
online: profiles get autosaved while in game, to prepare for serverside crashes
input: OIS updated, helps with certain mouse issues experienced by some (Windows only)
comms-truck: locations outside base centers supported
inkscape-tools: exporter now using parallel processing, more options

What does this mean?

It means the soldier continues to walk, which he started to do when firing, until he has pumped the shotgun. After that he'll start running.

In 0.80 and earlier versions, you were able to tap to shoot with a shotgun, the soldier would walk only while you had the mouse button pressed down, and would run right after the tap was done, effectively pumping while running.

Thanks.

This is horrible, the crouch walk slow down when you reload, but doesn't move when bolting?

Hmm, right, while crouched it indeed denies moving, that's too clunky. Maybe there's something to do about it for 0.82.