AVR-Chat

I am using TDC0 to time an incoming event.

At time 1 I set
 TDC0.CNT = 0x0000;
 TCD0.CCA = 0x0000;
 TCD0.PER = 0x065F;
 TCD0.CTRLA = TC_CLKSEL_DIV1_gc;

EVENT0 is supposed to capture the CNT into CCA when PortB pin1 signall is Rising.

I have added an overflow function (which is why "TCD0.PER = 0x065F;") in case there is no signal coming in and I set everything to defaults.

With no signal coming in (results are set to defaults).

at time 1
 TDC0.CNT = 0x0000 TCD0.CCA = 0x00 TCD0.PER = 0x065F
 TDC0 set to TC_CLKSEL_DIV1_gc
at time 2
 TDC0.CNT = 0x0254 TCD0.CCA = 0x00
at time 3
 TDC0.CNT = 0x03ce TCD0.CCA = 0x00

When TCD0 hits the overflow interrupt
 TDC0.CNT = 0x0043 TCD0.CCA = 0x00 TCD0.PER = 0x065f
 TDC0 set to TC_CLKSEL_OFF_gc

At end of Cycle
TDC0.CNT = 0x00b3 TCD0.CCA = 0x00

Now if I send in a pulse that causes Event0 (PortB1 rising) to capture the count this is what I get

at time 1
 TDC0.CNT = 0x0000 TCD0.CCA = 0x00 TCD0.PER = 0x065F
 TDC0 set to TC_CLKSEL_DIV1_gc
at time 2
 TDC0.CNT = 0x0255 TCD0.CCA = 0x00
at time 3
 TDC0.CNT = 0x03cf TCD0.CCA = 0x8260 (varies up to 8295)

When TCD0 hits the overflow interrupt
 TDC0.CNT = 0x003d TCD0.CCA = 0x8260 TCD0.PER = 0x065f
 TDC0 set to TC_CLKSEL_OFF_gc

At end of Cycle
 TDC0.CNT = 0x00ad TCD0.CCA = 0x8260

Why the HUGE number in CCA? I would think it to be around 0x0420 from tests on a previous system (using a 16A4).

If I add 0x7FFF to the 0x8260 then it looks like a sane/reasonable number for what I expecting.  So why is it so weird?

Is there something I'm doing wrong in my set up?
Before there was no Overflow in TCD0. Is there a problem with having a Capture and Overflow in the same timer?
I tried moving the Overflow out and doing the overflow processing on TCE1, but TCD0 is still out of it.

wade