CCS/MSP432P401R: I2C sending 1 write sequence, then getting stuck on busy even though both SCL and SDA are tied high

Part Number: MSP432P401R

Tool/software: Code Composer Studio

I am trying to communicate with a lidar (lidarlite) and am able to read from it continuously (if i don't write to it); If i try to write to it, one sequence is generated (with proper communication back), but after a significant delay, (to allow for the lidar to process) a second write (whether for read or write) is unsuccessful. the i2C module on the MSP seems to think the bus is busy, even though both lines are high and the first communication was successful; the second start condition never generates. 

all of this is on the msp432p401r Development board with the XDS110 debugger

What i have tried: using autostop with 2 bytes (commented out below); manually stopping; two stop conditions; resetting the module; changing modules (worked once, then same problem);

things verified: on the second time around: stop condition generated; after STOP, status says bus busy; UCTXSTT Bit is set; remains busy; 

Below is my code:

#include "msp.h"
#include <stdint.h>
#include <stdbool.h>
#include <debug.h>
#include "driverlib.h"
#include <stdint.h>
#include <string.h>
#include "i2c_driver.h"
#define SLAVE_ADDRESS 0x62

void main(void)//
{
WDT_A->CTL = WDT_A_CTL_PW | WDT_A_CTL_HOLD; // stop watchdog timer
//USING INTERNAL 12MHz CLOCK CODE
CS_setDCOCenteredFrequency(CS_DCO_FREQUENCY_12);
CS_setDCOFrequency(12000000); //TUNES TO 12MHz
MAP_CS_initClockSignal(CS_MCLK, CS_DCOCLK_SELECT, CS_CLOCK_DIVIDER_1);
MAP_CS_initClockSignal(CS_SMCLK, CS_DCOCLK_SELECT, CS_CLOCK_DIVIDER_1);
//--------------------initialize---------------------------------------------------
EUSCI_B3->CTLW0 = UCSWRST; //reset state
MAP_GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P10,
GPIO_PIN2 | GPIO_PIN3, GPIO_PRIMARY_MODULE_FUNCTION);
UCB3CTLW0 |= UCMST | UCMODE_3 | UCSYNC | UCSSEL_3 | UCTR;
//UCB3CTLW1 = UCASTP_2;
//UCB3TBCNT = 2; //auto stop at 2 bytes
UCB3BRW = 120;
UCB3I2CSA = SLAVE_ADDRESS;
EUSCI_B3->CTLW0 &= ~UCSWRST; //OUT OF reset state

while(1)
{
UCB3CTLW0 |=UCTR; //ensures in transmit mode for writing to register
UCB3CTLW0 |= UCTXSTT; //START condition; ALSO SENDS SLAVE ADDRESS
while ((UCB3CTLW0 & UCTXSTT)); //wait to stabilize
UCB3TXBUF = 0; //register of device for writing
while (!(UCTXIFG0 & UCB3IFG)); //wait for ACK,
UCB3TXBUF = 0; //command
while (!(UCTXIFG0 & UCB3IFG)); //wait for ACK,
UCB3CTLW0 |= UCTXSTP;
while((UCB3CTLW0 & UCTXSTP));//stop condition
__delay_cycles(220000);//allow for reset
UCB3CTLW0 &= ~UCTR;

};

}