Framing error if I disable transmitter after shift register is empty?

[Demon]

It's getting even dumber by the minute.

TX code on 1st 16F1937:

#CONFIG
 __CONFIG _CONFIG1, _FOSC_INTOSC & _WDTE_OFF & _PWRTE_ON & _MCLRE_ON & _CP_OFF & _CPD_OFF & _BOREN_OFF & _CLKOUTEN_OFF & _IESO_OFF & _FCMEN_OFF 
 __CONFIG _CONFIG2, _WRT_OFF & _VCAPEN_OFF & _PLLEN_OFF & _STVREN_OFF & _BORV_LO & _LVP_OFF
#ENDCONFIG

DEFINE OSC 32
SPLLEN          CON %1              ' PLL enable
IRCF            CON %1110           ' to enable 8 MHz
SCS             CON %00             ' system clock determined by FOSC
OSCCON = (SPLLEN << 7) | (IRCF << 3) | SCS

DEFINE  HSER_RCSTA 90h                          ' Enable serial port & continuous receive
DEFINE  HSER_TXSTA 24h                          ' Enable transmit, BRGH = 1
Define  HSER_BAUD 115200
DEFINE  HSER_CLROERR 1                          ' Clear overflow automatically
DEFINE  HSER_SPBRGH  0
DEFINE  HSER_SPBRG  68
BAUDCON.3 = 1                                   ' Enable 16 bit baudrate generator

ANSELA = %00000000
ANSELB = %00000000
'ANSELC = %00000000                      ' ...not available
ANSELD = %00000000
ANSELE = %00000000
TRISA = %00000000
TRISB = %00000000
TRISC = %10000000
TRISD = %00000000
TRISE = %00000000

BlinkLED                    VAR LatB.5

    Pause 200

    TXSTA.5 = 1                     ' TXEN: Transmit Enable bit
    hserout [   "[", 1, "]"]                             
    while TXSTA.1 = 0               ' Check TRMT: Transmit Shift Register Status bit
    wend
    TXSTA.5 = 0                     ' <----- Causes Framing error after last byte !

Mainloop:
    BlinkLED = 1
    BlinkLED = 0
    goto mainloop
end

RX code on 2nd 16F1937:

#CONFIG
 __CONFIG _CONFIG1, _FOSC_INTOSC & _WDTE_OFF & _PWRTE_ON & _MCLRE_ON & _CP_OFF & _CPD_OFF & _BOREN_OFF & _CLKOUTEN_OFF & _IESO_OFF & _FCMEN_OFF 
 __CONFIG _CONFIG2, _WRT_OFF & _VCAPEN_OFF & _PLLEN_OFF & _STVREN_OFF & _BORV_LO & _LVP_OFF
#ENDCONFIG

include "DT_INTS-14.bas"
include "ReEnterPBP.bas"
ASM
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler    RX_INT,  _ReceiveInterrupt,   PBP,  yes
    endm
    INT_CREATE               ; Creates the interrupt processor
ENDASM

DEFINE OSC 32
SPLLEN          CON %1              ' PLL enable
IRCF            CON %1110           ' to enable 8 MHz
SCS             CON %00             ' system clock determined by FOSC
OSCCON = (SPLLEN << 7) | (IRCF << 3) | SCS

DEFINE  HSER_RCSTA 90h              ' Enable serial port & continuous receive
DEFINE  HSER_TXSTA 24h              ' Enable transmit, BRGH = 1
Define  HSER_BAUD 115200
DEFINE  HSER_CLROERR 1              ' Clear overflow automatically
DEFINE  HSER_SPBRGH  0
DEFINE  HSER_SPBRG  68
BAUDCON.3 = 1                       ' Enable 16 bit baudrate generator

ANSELA = %00000000
ANSELB = %00000000
'ANSELC = %00000000                      ' ...not available
ANSELD = %00000000
ANSELE = %00000000                      ' Pin E0 = ADC input

TRISA = %00000000
TRISB = %00000000
TRISC = %10000000
TRISD = %00000000
TRISE = %00000000

LEDblink            var PORTD.0

RecvData                var BYTE[11]

    LEDblink = 0
    goto Start

ReceiveInterrupt:
    hserin [ wait("["), STR RecvData\11\"]" ]

    TXSTA.5 = 1
    hserout [   "[", 0, "]"   ]                            
    while TXSTA.1 = 0              ' Check TRMT bit
    wend
    TXSTA.5 = 0

@ INT_RETURN

Start:
    Pause 200                           ' Let PIC and LCD stabilize
    
@   INT_ENABLE   RX_INT

Mainloop:
    LEDblink = 1
    LEDblink = 0
    GOTO Mainloop
end

The RX PIC has the exact same HSEROUT code:
- enable transmitter
- transmit data
- wait until buffer is empty
- disable transmitter


DISABLE transmitter causes a FRAMING ERROR on 1st PIC, but not on Ack message on 2nd PIC.



This has to be a really stupid error cause there's practically no code left.


EDIT: Does it make a difference if I disable transmitter inside the Interrupt routine?

EDIT SOME MORE: I moved the DISABLE out of the ISR and into Mainloop, it didn't make a difference during RX on the 2nd PIC.