QTCreator: GDB debugs code once, then drops to assembly - c++

Question

Using Qt 5.1.1 for Windows 32-bit (with MinGW 4.8), when debugging GDB wants to drop into dissassembly while debugging code after the first time.
I make a "Plain C++" project, insert some simple code:
int x = 5;
cout << x << endl;
return 0;
Build, and debug it with a breakpoint on first line. First time through it debugs just fine stepping through the code with "Step Over". Any debug session after that, it will drop into dissamebly view of ntdll when it hits cout (or anything else library related).
Operate By Instruction is not checked and there is debug information for my code. It works as expected once, then refuses to.
I can delete the build folder and the .pro.user file and the project still exhibits the same behavior after a new build. Even tried wiping my QTProject settings folder. There seems to be no way to debug just my code more than once without it wanting to drop into assembly instead of stepping over statements. If I make a new project, I can debug it normally once, then it starts behaving the same way.
Looking for a fix or suggestions of things to try.
Had a chance to go back...diffed the debugger log on the good initial vs sequential runs. Everything looks similar until I get to this in good run:
=thread-exited,id="2",group-id="i1"
sThread 2 in group i1 exited
~"[Switching to Thread 5588.0x239c]\n"
=thread-selected,id="1"
sThread 1 selected
Bad runs never have that. Later, this is unique to bad run:
>1272^done,threads=[{id="2",target-id="Thread 7148.0x242c",frame=
{level="0",addr="0x7792fd91",func="ntdll!RtlFindSetBits",args=
[],from="C:\\Windows\\system32\\ntdll.dll"},state="stopped"},
//LINES BELOW COMMON TO GOOD+BAD
{id="1",target-id="Thread 7148.0x1bbc",frame=
{level="0",addr="0x00401606",func="main",args=
[],file="..\\untitled8\\main.cpp",fullname=
"C:\\Users\\Andrew\\Desktop\\untitled8\\main.cpp",line="7"},
state="stopped"}],current-thread-id="1"*
Then once it hits the breakpoint, good run shows this:
*stopped,reason="end-stepping-range",frame={addr="0x00401620",func="fu0__ZSt4cout",args[],
file="..\untitled8\main.cpp",
fullname="C:\Users\Andrew\Desktop\untitled8\main.cpp",line="9"},
thread-id="1",stopped-threads="all"
Bad run shows this:
>*stopped,reason="signal-received",signal-name="SIGTRAP",signal-meaning="Trace/breakpoint trap",
frame={addr="0x7792000d",func="ntdll!LdrFindResource_U",args=[],
from="C:\\Windows\\system32\\ntdll.dll"},thread-id="2",stopped-threads="all"
dNOTE: INFERIOR SPONTANEOUS STOP sStopped.
dState changed from InferiorRunOk(11) to InferiorStopOk(14) [master]
dSIGTRAP CONSIDERED HARMLESS. CONTINUING.
sStopped: "signal-received"
>=thread-selected,id="2"
sThread 2 selected
<1283-thread-info
>1283^done,threads=[{id="2",target-id="Thread 7148.0x242c",frame=
{level="0",addr="0x7792000d",func="ntdll!LdrFindResource_U",args=[],
from="C:\\Windows\\system32\\ntdll.dll"},state="stopped"},
{id="1",target-id="Thread 7148.0x1bbc",
frame={level="0",addr="0x756a133d",func="KERNEL32!GetPrivateProfileStructA",
args=[],from="C:\\Windows\\syswow64\\kernel32.dll"},state="stopped"}],current-thread-id="2"
<1284-stack-list-frames 0 20
>1284^done,stack=[frame={level="0",addr="0x7792000d",func="ntdll!LdrFindResource_U",
from="C:\\Windows\\system32\\ntdll.dll"},
frame={level="1",addr="0x779af926",
func="ntdll!RtlQueryTimeZoneInformation",
from="C:\\Windows\\system32\\ntdll.dll"},frame={level="2",addr="0x75f45dd1",func="??"},
frame={level="3",addr="0x00000000",func="??"}]
<1285-stack-select-frame 0
<1286disassemble 0x7791fff9,0x77920071
<1287bb options:fancy,autoderef,dyntype vars: expanded:return,local,watch,inspect typeformats: formats: watchers:
>1285^done
>&"disassemble 0x7791fff9,0x77920071\n"
>~"Dump of assembler code from 0x7791fff9 to 0x77920071:\n"
>~" 0x7791fff9 <ntdll!LdrFindResource_U+60953>:\t"
>&"Cannot access memory at address 0x7791fff9\n"
>1286^error,msg="Cannot access memory at address 0x7791fff9"
sDisassembler failed: Cannot access memory at address 0x7791fff9
Looks like for some reason that extra thread is not exiting when expected and qtcreator/gdb convince themselves there are breakpoints in ntdll that I want to stop at.