This is a also happening on my iMac as well. Every time I think I'm getting to the culprit, the following always seems to appear in the crash dump:
Heaviest stack for the main thread of the target process:
11 ??? (iTunes + 9028) [0x1086d7344]
11 ??? (iTunes + 8615238) [0x108f0c546]
11 -[NSApplication run] + 594 (AppKit + 551667) [0x7fff83ffdaf3]
11 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 346 (AppKit + 593496) [0x7fff84007e58]
11 _DPSNextEvent + 978 (AppKit + 596139) [0x7fff840088ab]
11 _BlockUntilNextEventMatchingListInModeWithFilter + 71 (HIToolbox + 205099) [0x7fff8b26e12b]
11 ReceiveNextEventCommon + 431 (HIToolbox + 205546) [0x7fff8b26e2ea]
11 RunCurrentEventLoopInMode + 235 (HIToolbox + 206191) [0x7fff8b26e56f]
11 CFRunLoopRunSpecific + 296 (CoreFoundation + 465880) [0x7fff8299abd8]
11 __CFRunLoopRun + 927 (CoreFoundation + 467391) [0x7fff8299b1bf]
11 __CFRunLoopDoSources0 + 269 (CoreFoundation + 469901) [0x7fff8299bb8d]
11 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17 (CoreFoundation + 526849) [0x7fff829a9a01]
11 ??? (iTunes + 9347552) [0x108fbf1e0]
11 ??? (iTunes + 9347354) [0x108fbf11a]
11 ??? (iTunes + 9344338) [0x108fbe552]
11 ??? (iTunes + 8465590) [0x108ee7cb6]
11 ??? (iTunes + 6797705) [0x108d50989]
11 ??? (iTunes + 6796658) [0x108d50572]
11 ??? (iTunes + 6800151) [0x108d51317]
11 mach_msg_trap + 10 (libsystem_kernel.dylib + 70878) [0x7fff8282d4de]
*11 ipc_mqueue_receive_continue + 0 (kernel + 1148928) [0xffffff8000318800]
Process: iTunes [1845]
Path: /Applications/iTunes.app/Contents/MacOS/iTunes
Architecture: x86_64
Parent: launchd [1]
UID: 501
Task size: 12657 pages
Note: Unresponsive for 332 seconds before sampling
Thread 0x26291 DispatchQueue 1 11 samples (1-11) priority 46
<thread QoS user interactive, boosted, received importance donation from WindowServer [286], IO policy important>
11 ??? (iTunes + 9028) [0x1086d7344] 1-11
11 ??? (iTunes + 8615238) [0x108f0c546] 1-11
11 -[NSApplication run] + 594 (AppKit + 551667) [0x7fff83ffdaf3] 1-11
11 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 346 (AppKit + 593496) [0x7fff84007e58] 1-11
11 _DPSNextEvent + 978 (AppKit + 596139) [0x7fff840088ab] 1-11
11 _BlockUntilNextEventMatchingListInModeWithFilter + 71 (HIToolbox + 205099) [0x7fff8b26e12b] 1-11
11 ReceiveNextEventCommon + 431 (HIToolbox + 205546) [0x7fff8b26e2ea] 1-11
11 RunCurrentEventLoopInMode + 235 (HIToolbox + 206191) [0x7fff8b26e56f] 1-11
11 CFRunLoopRunSpecific + 296 (CoreFoundation + 465880) [0x7fff8299abd8] 1-11
11 __CFRunLoopRun + 927 (CoreFoundation + 467391) [0x7fff8299b1bf] 1-11
11 __CFRunLoopDoSources0 + 269 (CoreFoundation + 469901) [0x7fff8299bb8d] 1-11
11 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17 (CoreFoundation + 526849) [0x7fff829a9a01] 1-11
11 ??? (iTunes + 9347552) [0x108fbf1e0] 1-11
11 ??? (iTunes + 9347354) [0x108fbf11a] 1-11
11 ??? (iTunes + 9344338) [0x108fbe552] 1-11
11 ??? (iTunes + 8465590) [0x108ee7cb6] 1-11
11 ??? (iTunes + 6797705) [0x108d50989] 1-11
11 ??? (iTunes + 6796658) [0x108d50572] 1-11
11 ??? (iTunes + 6800151) [0x108d51317] 1-11
11 mach_msg_trap + 10 (libsystem_kernel.dylib + 70878) [0x7fff8282d4de] 1-11
*11 ipc_mqueue_receive_continue + 0 (kernel + 1148928) [0xffffff8000318800] 1-11
So there's something extremely wrong with the current iTunes ver. 12.2.1.