DTS and PTS are different, despite not having B-frames (ffmpeg)

Just a quick question in regards to video encoding/muxing a video file with ffmpeg. Basically, I have my muxer functioning and I'm trying to have my packets output the correct PTS/DTS.

This is a portion of my code that encodes my AVFrame, muxing it to an output file:

int ret;
int got_packet = 0; AVPacket pkt = { 0 };
av_init_packet(&pkt); pkt.data = NULL;
pkt.size = 0; /* encode the image */
ret = avcodec_encode_video2(cc, &pkt, frame, &got_packet);
if (ret < 0)
{ fprintf(stderr, "error encoding video frame: %s\n", av_err2str(ret)); exit(EXIT_FAILURE);
} if (got_packet)
{ av_packet_rescale_ts(&pkt, cc->time_base, st->time_base); fprintf(stderr, "\npkt.pts = %ld\n", pkt.pts); fprintf(stderr, "pkt.dts = %ld\n", pkt.dts); fprintf(stderr, "writing frame\n"); ret = av_interleaved_write_frame(fmt_ctx, &pkt); av_packet_unref(&pkt);
}
else
{ ret = 0;
} ...

I'm then getting an output of the following:

pkt.pts = 0
pkt.dts = 0
writing frame pkt.pts = 1502
pkt.dts = 0
writing frame pkt.pts = 3003
pkt.dts = 1502
writing frame pkt.pts = 4505
pkt.dts = 3003
writing frame ...

My goal is to have my PST and DST both with the pattern: 1502, 3003, 4505, 6006, 7508, ...

But it seems that the first DTS value is repeating once, and thus being off-sync with it's corresponding PTS value. It's also worth mentioning that the codec context was configured to have no b-frames, so only i- and p- frames are present here.

Does anyone with more experience have some insight on this?

Addition:

I ran the following command in terminal to check if my DTS and PTS values were consistent to my print statements:

sudo ./ffprobe -show_packets -print_format json mux_test.ts | less

And I got the following:

{ "packets": [ { "codec_type": "video", "stream_index": 0, "pts": 0, "pts_time": "0.000000", "dts": -1501, "dts_time": "-0.016678", "duration": 1501, "duration_time": "0.016678", "convergence_duration": "N/A", "convergence_duration_time": "N/A", "size": "55409", "pos": "564", "flags": "K" }, { "codec_type": "video", "stream_index": 0, "pts": 1502, "pts_time": "0.016689", "dts": 0, "dts_time": "0.000000", "duration": 1501, "duration_time": "0.016678", "convergence_duration": "N/A", "convergence_duration_time": "N/A", "size": "46574", "pos": "60160", "flags": "_" }, { "codec_type": "video", "stream_index": 0, "pts": 3003, "pts_time": "0.033367", "dts": 1502, "dts_time": "0.016689", "duration": 1501, "duration_time": "0.016678", "convergence_duration": "N/A", "convergence_duration_time": "N/A", "size": "2544", "pos": "110356", "flags": "_" }, ...

Which doesn't show my first DTS value repeated, but continues to show my DTS one cycle behind my PTS.