As @dbmandrake notes, do the pitch bends occur near an ad break? It can happen with poor quality rips.
No, you’re not because this is a feature of Kodi. 
As Sam already suggests you’re probably playing content which contains different frame rates and then Kodi has to switch. One of the options is to re-sample the audio to match this new rate, go to http://kodi.wiki/view/Settings/Videos and then lookup info under A/V sync method.
For future ref and anyone reading with the same issue.
This will seem obvious to most here no doubt, but when trying to add a smb share i needed to use the syntax:
smb://IPADDRESS/SHARE
Since moving away from wireless I’ve had a few less issues, still getting some audio issues which i’ll try and recreate and do logs for. The files randomly stopping when seeking through them happens a lot less when not on wireless.
I’ve noticed when using the on screen diagnostics that i tend to always get some “skipped” frames, these MIGHT be lining up with the audio glitches, going to pay more attention to this.
Please also explain/detail a little bit your data-source. NAS, what CPU is inside/memory and which network-speed connection is provided.
I noticed that a NAS with weak I/O capability or slow CPU can’t react fast enough when several devices access the data (Since I have 6 devices sometimes accessing at the same time, a ATOM 1.9Ghz CPU + 2GB Ram was not enough).
Also, I completely moved away from SMB. That is the “sickest” protocol to use and was developed by Microsoft in the beginning to just provide fiel access. The security and other features have been added over time as an add-on, and the code has not gotten slimmer in that process.
If you can, use NFS.
As I said - I have 6 devices (2 Vero’s, 4 Raspberry PI’s and one other computer) using kodi to access that device. Not talking about the other 10 devices doing/saving/cloud storing data on the NAS.
NAS is a HP Microserver gen8, Xeon 2.2Ghz CPU + 16GB Ram, and 4x4TB disk as Raid-5.
But I explicitely use NFS, and the one apple device we have uses AFP, but I limited it to timemachine backups.
The Disk subsystem delivers around 800Mbytes/s data, and I have around 300Mbytes/s write speed - which is what is required with all my “girls” doing crazy stuff in the lan 
My file server runs on W7 so i don’t think NFS is an option, but i’ll look into it.
Its an older Intel chip the Q6600 which is a quad core 2.4Ghtz, 4GB RAM, NAS hard drives on a gigabit link, so theres no issues there. (Though the LAN link is obviously limited at the Vero end to 100Mbs).
I really think most of the issues you see here would go away when not using Win7.
I bet you also have a AV running on it, and lots of crap services Microsoft adds here anyway you can’t remove.
I’m using Openmediavault (http://www.openmediavault.org/ ) which is actually dedicated to be a File Server for the home network. There are no extras, and it is fine-tuned to do exactly that one job. And - you have a decent web-based UI for configuration and setup.
@sam_nazarko & @ActionA: Eventually we should setup a listing for devices/setup that may act as a NAS/File Server for kodi somehow. And also add some “points” on how well these perform with OSMC/Kodi. Like:
Device, hardware description, network type used (WiFi/Cat6), network filesystem used, Db Backend etc.
I’m not really sure how. Its been up and running for years, serving media to 3 TVs, a raspberry pi running OSMC, 3 phones and 2 laptops (including a test where i ran films on literally all of these devices at once with zero issues)
If you have your files on a Win7 PC which is running all the time, i would install kodi on that machine and add the sources to the kodi library of the win7 machine.
Than you can access your files by selecting the win7 kodi as source. There are no problems with streaming for me.
So give it a try
OK. Ok. You got me there…
Didn’t look into that