Usually shortages show up when prices can’t adjust freely.
They show up anytime demand outstrips supply. Pricing problems are the most familiar but in this case there's a fundamental issue with infrastructure. Building EV Chargers is long term work that requires shedloads of money to be invested in both the charging points themselves and the electrical infrastructure required to power them; everything from power generation to transmission.
You can build 1,000 EVs in week but building a charging station for them could easily take two years and require a hundred million dollars. We're building EVs so fast that the infrastructure part simply can't keep up.