That's not what this data says.
What's happening is that in cases of overdose deaths, both causative and contributing drugs get listed in this report. We have a hint in the description of the data, which states, "When comparing deaths by drug type, multiple drugs are often listed for one death." According to the data table, statistics are generated using ICD codes:
Deaths are classified using the International Classification of Diseases, 10th Revision. Preventable drug poisoning deaths are identified using underlying cause-of-death codes X40-X44, while all drug poisoning deaths are identified by codes X40-X44, X60-X64, X85, and Y10-Y14.
Among deaths with drug overdose as the underlying cause, the following multiple cause-of-death codes indicate the drug type(s) involved: Any opioid (T4NR-T40.4, T40.6), heroin (T40.1), methadone (T40.3), synthetic opioids other than methadone (including fentanyl, T40.4), natural and semisynthetic opioids (including oxycodone and hydrocodone, T40.2), benzodiazepines (T42.4), cocaine (T40.5), and cannabis (T40.7). Deaths involving more than one opioid category are counted in both categories.
Digging into the ICD codes a little deeper, however, we find this information, emphasis mine:
Codes for underlying cause of overdose death include the letter X or Y
(for example, X40: accidental poisoning, X60: intentional self-harm).
Codes for opioid-related contributing cause of overdose death
include a T (for example., T40.1: heroin, T40.4: other synthetic
So, cannabis is only uniquely identifiable in this dataset under code T40.7, which merely indicates a "contributing cause" but not an "underlying cause" of death. I can't find any ICD code that denotes cannabis as an underlying cause of death - one might infer from the lack of such a code that fatal cannabis overdose is exceedingly rare.
Overall, it seems this data indicates that there were 1,130 people that died from a drug overdose who had marijuana listed as a contributing - but not principally causative - factor in the death. The data does not indicate that there were 1,130 deaths whose underlying cause was cannabis overdose.
It is possible that there are deaths caused by cannabis overdose which appear in other categories, but from this data there is no way to ascribe a number specifically to cannabis. It's theoretically possible that over 1000 fatal cannabis overdoses appear in other categories, but it seems medically unlikely. While we can't conclude from this data that there aren't over 1000 fatal cannabis overdoses, we also can't conclude from this data that there's even 1 fatal overdose caused by cannabis.